Quantitative methods in psychology exam 1, Exam 1 All, Kilianski Exam 1 Quantitative Methods conceptual, Quantitative Methods Exam 1, Quantitative Methods in Psychology: Exam 1
Dependent Variable
"Effect" in an experiment, the effect or criteria in an experiment, the outcome
For Anova, dfb is
#means -1
Whether or not a mean difference between two samples is statistically significant depends on
1. the magnitude of the difference 2. the size of the sample 3. the amount of random variation within each sample
If the Pearson's r between variables X and Y is -.50, how much of variance in Y can be predicted by X?
25%
A study is being conducted by the US Agricultural Service on the effects of fertilizer (high nitrogen, high sulfur, high potassium) Six randomly selected groups of corn plants are exposed to one of the combos of conditions for 3 months, then the plant height is measured in inches. We should analyze the data with
2x3 factorial ANOVA
A five group reserach design with six subjects in each group has ____ degrees of freedom and _____ within degrees of freedom
4, 25
In any t-test what influences whether or not we reject the null?
A.the size of the difference between means B.the sample size C.the sample SD
Using an alpha of .05 means the probability of making a Type I error is A. 95% B. 5% C. 50% D. It depends on degrees of freedom
B
When doing a t-test, our obtained t-value must ________ the critical value in the table (for the designated degrees of freedom) in order to _________ the null hypothesis. A. be less than; reject B. be equal to or greater than; reject C. be equal to or greater than; accept D. equal; prove
B
With respect to estimating a population mean, compared to a 99% confidence interval, a 95% confidence interval will be A. wider B. narrower C. the same D. it depends on the size of the std. deviation(s).
B
In estimating the standard error of the mean, we use the sample SD, but then divide it by the square root of N-1 instead of N. Why? A. The sample SD is a biased estimate, consistently overestimating the population SD B. The sample SD is a biased estimate, consistently underestimating the population SD C. Dr. Kilianski and the text author say to do it that way. D. An uppercase N has an inflated ego, and needs a correction factor to induce some humility.
B.
Why is the term 2r(SEM1)(SEM2) not included in the independent samples t-test?
Because the r is assumed to be 0 in the independent samples t-test
A non-representative sample is often due to ___________, which is constant sampling error in one direction.
Bias
Bigger the Ind Var., _____ the F will be, more ____ to reject the null
Bigger, Bigger, Likely
Interval Ratio Data
Can be measured, etc. ratio variables have true 0 value, not celsius or fahrenheit, Interval variables have arbitrary 0 values.
Median
Center score, equal number below or above of scores (measure of central tendency)
Alpha Level- Type 1 Error
Chance that we would reject, probability we are wrong
The range of the mean values within which the true parameters mean is predicted to fall is called _____.
Confidence Interval
When we reject the null hypothesis
we determine that the null hypothesis is unlikely to be true
The MAIN reason we never prove anything in social science research is that
we draw conclusions about populations from sample data
We can only use the z-test when we are comparing a sample mean to a known population mean and
we have the population standard deviation
To establish a "significant difference", what decision must first be made regarding the null hypothesis?
whether or not to reject the null hypothesis
When estimating a population mean using confidence intervals, what determines whether you use a value from the t-table or the z-table?
whether you have a population standard deviation
With respect to estimating a population mean, compared to a 95% confidence interval, a 99% confidence interval will be
wider
The sampling distribution of the mean has a standard deviation referred to as the A. normal standard deviation B. the standard error of the difference C. the variance of the population D. the standard error of the mean
D
In a single-sample t-test, as the sample SD increases, the size of the obtained t-value ____, making it ______ likely to reject the null hypothesis. A. increases; more B. increases; less C. decreases; more D. decreases; less
D Feedback: since the SD is the main component of the denominator in the ratio, the larger it gets, the lower the t-ratio becomes. You need to equal or exceed the critical value of t (from the table) to reject the null, so a smaller t makes it less likely that you will do so.
The Standard error of the difference is literally the Standard deviation of which important sampling distribution?
Difference
Ordinal
Elements can be arranged in a hierarchy, indicates relative position, so >or < do apply, but intervals between positions are unknown
In linear regression, if the slope is -.25,
Every unit increase in X will result in a 1/4 unit decrease in Y
In an ANOVA design, as the scores within each cell vary from each other less, the _____ will ________
F ratio;increase
A Pearson's r of +.50 has a higher coefficient of determination (ie yields greater predictive accuracy) than an 7 of -.70 T/F
False
If sample sizes are large, bias is eliminated.
False
In linear regression, the intercept is the value of X when the value of Y is 0.
False
Interval
Has an "arbitrary" zero, does not represent the property, absolutely nothing
Mode
Most frequently occuring value (measure of central tendency)
The two samples represent a single Population.
Null hypothesis
Any measurement made on the entire population is called a(n) __________.
Parameter
Statistic or Parameter? Population mean (m (mue))
Parameter
Measurement
Quantifies the variables of interest, relies on reliability and validity
Post-Facto/Non-Experimental Research
Research where you can't draw causal conclusions. Variables cannot be controlled only measured.
Expiriments
Researcher controls (manipulates) an IV by random assignment
Reliability
Similar to a bathroom scale, needs to be consistant, isn't sufficient enough for validity
Statistic or parameter Standard deviation of the sample.
Statistic
Mean
The average(measure of central tendency)
Sample mean is...
The point estimate of the population
When samples are selected randomly from a single population, a.) the probability of selecting a sample whose mean is higher than the population mean is __________. b.) the probability of selecting a sample whose mean is lower than the population mean is __________.
a.) 50 % b.) 50 %
The denominator in the F ratio represents the variation in the dependent variable due to chance and
all factors except the independent variable
With respect to experimental data, the DENOMINATOR in the t-ratio represents the variation in the dependent variable due to
all sources of variation except the independent variable
Further the means are, the _________ the ________ variable
bigger, ind.
In a repeated measures t-test, as the correlation between the before and after score decreases, the probability of rejecting the null hypothesis
decreases
Using an alpha of .01 instead of .05
decreases the probability of making a Type I error
With respect to the paired-samples t-test, as the size of the r increases, the t-ratio _____ making it ________ to reject the null hypothesis.
increases; more likely
When all assumptions are met, the paried t ratio is _____ than the independt t to reject the null when only a small difference exists between the sample means
more able
With pearsons r the sign is not related to the _____ of the relationship
strength
If we were to create a frequency distribution of differences between pairs of sample means taken from the same population, which of the following would be FALSE about that distribution
the mean of the distribution would be equal to the population mean
Which of the following is used in determining the degrees of freedom between in the F-test?
the number of groups being compared
The definition of the term "degrees of freedom" refer to what
the number of values in the data that are free to vary
The degrees of freedom for the chi-square statistic is influenced by
the number or rows and columns in the contingency table
What's a negative skew?
If the mean(average) is less than the median
Pearsons R
Interval Ratio (x,y) Linear Homoscedastic
Manipulated
Makes it an expiriment
Range
Maximum-the minimum (1-5million dollars a year)
For the single-sample t ration, degrees of freedom are equal to _____________.
N - 1
For Anova, dfw is
N- # of groups
In regression analysis, the intercept is determined by what factors
- mean of Y - mean of X - the slope of the regression line
Experimental Method
-Manipulate variable of interest, control other -random assignment, controlling, independent variable, dependent variable, experimental condition, control condition, confounding variables
Z-Score
-Number of standard deviations a score is from the mean - z= (X-μ)/σ - (+)= above mean, (-)= below mean - the mean for a z-score is always 0 -the standard deviation is always 1
Histograms
-Used for interval or ratio scales -Bars touch to represent a continuous variable
Factors that effect Pearson's r
1. restricted range 2. outliers
ANOVA demands that at least ___ sample groups must be compared
2
Using an alpha of .05 means the probability of making a Type I error is
5%
With a confidence interval of .95, the probability of not including the parameter mean is equal to ____ or less.
5%
With a confidence interval of .95, the probability of not including the parameter mean is equal to __________ or less.
5%
Which of the following is FALSE with respect to the standard deviation? A. It can never be 0 B. It can never be negative C. It can never be more than ½ the range. D. It functions as the denominator when computing a z-score
A. It can be 0 if all scores are identical
Inferential Statistics
All about letting us draw conclusions from a sample data, all about probability
With respect to the level of measurement, for a chi-square test, the dependent variable is _____ and the independent variable is ______. A. nominal; interval/ratio B. interval/ratio; nominal C. nominal; nominal D. interval/ratio; interval/ratio
C
If a researcher wanted to determine if there was a difference between a sample of Democrats and a sample of Republicans in their annual income (measured in dollars) the appropriate inferential statistic to use would be the A. z-test B. chi-square test C. single-sample t-test D. independent samples t-test
D
The null hypothesis for the single-sample t-test is that any difference between the sample mean and the population mean is due to A. chance B. random variation C. sampling error D. all of the above E. none of the above
D
When you know the population mean, but the population standard deviation is unknown, and you want to determine if a sample mean is "significantly different" from the population mean, you should use a(n) A. z-test B. independent samples t-test C. repeated measures t-test D. single-sample t-test
D
If the correlation between X and Y is zero, the best predictor of the value of Y is the mean of X.
False
With respect to estimating a population mean, compared to a 99% confidence interval, a 95% confidence interval will be
Narrower
Degrees of Freedom
Number of Values that are free to Vary
Statistics is to sample as __________ is to population.
Parameter
When the calculated value of t is equal to or greater than the table value of t for a given number of degrees of freedom, the researcher should _______________ the null hypothesis.
Reject
Errors of prediction
Residuals
If the null is smaller the ______ decreases
Standard error of the mean
When an ANOVA results in the rejection of the null hypothesis, the between-group variability must be greater than the within-group variability.
True
SD
average distance from the mean in a set of scores, it is the square root of the sum of x minus m squared divided by N Interval Ratio data only
Why do we conduct a post-hoc test if we find a significant F in a one-way ANOVA?
because we dont know which means differ from which other ones when there are more than 2 of them
With respect to the "sampling distribution of the mean,"
both A and B are true
pearsonss R
cant be non-linear - cant be ordinal
The null hypothesis for the single-sample t-test is that any difference between the sample mean and the population mean is due to
chance, random variation, sampling error
The t ration tells us by how much the difference between the sample means deviates from a mean difference of zero in units of what?
est SE diff
The to-ratio tells us by how much the difference between the sample means deviates from a mean difference of zero in units of what?
est. SED
ANOVA assumes that data are at least
interval
When S.D. is less than 1/6th of the range we have a _____
less, 1/6th, lepot
When S.D. is 1/6th of the range we have a _____
mesok
________ is a parameter, while ________ is a statistic.
mew;SD
Sampling Distribution MUST be:
normal, equal to population mean, has an SD (SEM)
the two samples represent a single population.
null hyporthesis
The statement that the sample is representative of the same parameter as that assumed for the population at large is called the ___________ hypothesis.
null hypothesis
m1 = m2 (m=mue)
null hypothesis (independent sample t-test)
Inferential statistics are referred to as 'inferential' because they are used to draw conclusions about ___ from ___.
populations; samples
A researcher predicts that as anxiety increases, performance on a test of math skills will decrease. The researcher's hypothesis is
r population < 0
Experimental Condition
receives experimental treatment
Statistics
refers to a set of mathematical procedures for organizing, summarizing, and interpreting information
A point estimate is a hypothesized parameter value that is based on a (n) __________ value.
sample (statistical)
We use a Z- Test to
see how close to the population mean we are
Negative Skew
tail on left side, peak on right
Reliability
the consistency of a measurement, that every time you measure something it comes back the same(regardless of its validity, example: if a scale gives the SAME but incorrect measure every time than it IS RELIABLE)
The larger the F ratio
the more likely we are to reject the null hypothesis
Which of the following is used in determining the degrees of freedom between in the F-test?
the number of groups prepared
Degrees of freedom in a chi-square test is determined by
the number of rows and columns in the design
When you know the population mean and the population standard deviation, and you want to determine if a sample mean is significantly different from the population mean, you should use the
z-test
Bar Graphs
-Used for nominal or ordinal scales -space between bars to represent discrete categories
.
.
Factorial Anova is when you havw more than _____ individual variable.
1
A pearsons R of .90 means that the percentage of a cause and effect relationship is
81%
If we use an alpha of .01 when testing the null hypothesis, what is the probability of making a Type II error?
99%
The probably of committing the Type1 error, or of being wrong wrong when The null hypothesis is rejected.
Alpha Level
If we do not have the population SD, why can we not use the z-table to determine whether a sample mean is representative of a population?
Because we must estimate the SEM and the hypothetical distribution is more platykurtic except at N=infinity
. If we use an alpha of .01 when testing the null hypothesis, what is the probability of making a Type II error? A. 1% B. 50% C. 99% D. You cannot tell from the information given because you need mean differences, sample size, and std. deviations to determine that.
C
A negative z-score means that the value is A. in a negative percentile rank B. probably due to sampling error C. between the 0 and 50th percentile D. impossible; you can never have a negative z-score
C
When we fail to reject H0, we are concluding that the results (e.g., the difference between means) are due to A. the independent variable B. the dependent variable C. sampling error D. none of the above
C
Does setting alpha at .01 rather than at .05 increase or decrease the likelihood of rejecting Ho (the null hypothesis)?
Decrease
Independent Variable
Determiner
Deviations from all the lines are ___________________
Errors of prediction `
Nonderectional two tailed test of differences among sample groups used whenever ythe data are in interval form
F-ratio
Whenever there is more than one indenpendt variable and the data is in interval form
Factorial annova
The sample size has no impact on the mean square within T/F
False
Which of the following is FALSE with respect to the standard deviation?
It can never be 0
Given a data set with a standard deviation of 7 and a range of 60, you should conclude that the distribution i
Leptokurtic
Given a data set with a standard deviation of 7 and a range of 60, you should conclude that the distribution is
Leptokurtic
Inferential statistics
Making inferences based on probability about an entire population using data from a sample
If SD=1/6 of the range(normal)
Mesokurtic
State how the degrees of fredom compare between the in. and paired t ratios
N1
In a sample of high school runners' times in the 1600 meters, the mode was 4:50, the mean was 4:35, and the median was 4:42. What can we say about the distribution?
Negatively Skewed
If a researcher asks subjects to identify their sexual orientation as either heterosexual, homosexual, or bisexual, sexual orientation is being measured on an _______ level.
Nominal
The central limit theorem stated that the shape of the entire distribution of sample means will tend to approximate _____________.
Normal curve
If SD>1/6 of the range
Platykurtic(flat)
M
Point estimate for a population mean, a point estimate for the μ, the sample represents
The total number of observations shares at least one trait in common is called the _______.
Population
Inferential statistics are referred to as 'inferential' because they are used to draw conclusions about ___ from ___
Populations; Samples
Levels of Measurement
Primary determinant of descriptive and inferential methods you can use, includes Nominal, Ordinal, and Interval/ Ratio
A method of sampling in which every observation in the entire population has an equal chance of being selected is called__________.
Random Sampling
Error
Random Variation, not a mistake and it occurs by chance
Type 1 error
Reject null when null is true
Variance
SD squared, interval ratio data only
Lepotokurtic
SD< 1/6R
Sample
Subset of a population, "representatives". Example: 500 students who can vote at Rutgers
Independent Variable
The "cause", the thing that the researchers are going to manipulate the predictor
At a given t-value, the smaller the sample size
The less likely we are to reject null
Because of sampling error, a point estimate can never be guaranteed to produce the true population parameter.
True (samples only make inferences)
When the null hypothesis is rejected, even though it should not have been rejected, the ________ error has been committed.
Type 1
When we have to compare the mean of more than two groups, we use the 1-way ANOVA. Why don't we use t-tests to compare each pair of means?
Using repreated t-tests would increase the probability of rejecting the null hypothesis when it in fact true to greater than .05
X
Value, usually at zero, represents the value of the variable
Distributional Skew
Which side of the chart the data clusters at(not where the mode is at)
The higher the correlation between X and Y the more information about ______
Y is contained in X
Variable
a characteristic or condition that changes or has different values for different individuals
A researcher wants to find out if watching TV has an effect on students academic performance. For one semester she has them watch 20 hours per week and another semester has them watch none. She then compares their GPAs from both semesters. Which test should be used?
a two-tailed paired samples t-test
Statistic
a value, that describes a sample
The probability of committing the Type 1 error, or of being wrong when the null hypothesis is rejected.
alpha level
m1 doesnt = m2 (m=mue)
alternative hypothesis
When doing a t-test, our obtained t-value must ________ the critical value in the table (for the designated degrees of freedom) in order to _________ the null hypothesis.
be equal to or greater than; reject
Why is the term 2r(SEM1)(SEM2) not included in the independent samples t-test?
because R is assumed to be 0 in the independent samples t -test
the greater the spread among the various sample means, the larger the _____ variablity
between
The null hypothesis for the single-sample t-test is that any difference between the sample mean and the population mean is due to
chance, sampling error, random variation
If we wanted to determine whether a sample of male and female voters differed in their preference for a particular candidate (i.e., for which one would they vote), we would use the
chi-square test
The higher the pearsons R, the higher is the
coefficant of determinationq
The range of mean values within which the true parameter mean is predicted to fall is called the __________.
confidence interval
Before conducting a multiple regression analysis, we need to
confirm that each of the hypothesized predictors has a significant Pearsons r with the criterion variable
As sigma gets smaller, the standard error of the mean would...
decrease
An estimate of the standard deviation of the entire distribution of differences.
est SE diff
The t-test or the z-test can be used if the dependent variable is nominal.
false
In linear regression analysis, if the slope is +.50,
for every unit increase in X there will be 1/2 a unit increase in Y
As the value of an inferential statistic (e.g. t, z, x^2) decreases, the probability that the null hypothesis is true
increases
For equal number of scores, the paired t has more degrees of freedom than the
indepdent t
Which of the following is FALSE with respect to the standard deviation?
it can never be 0
Errors of prediction increase with
larger risduals
If the within group v. is small, yhen the seperate sample groups are most likely to have _____ distributuonsq
leptokurtic
The sampling distribution of the ______ is a frequency distribution of an infinite number of _______taken from the same _______
mean;sample means;population
Using statistical notation, the hypothesis for the 2 tailed z-test would be
mew sample = mew population
With respect to the level of measurement, for a chi-square test, the dependent variable is _____ and the independent variable is ______.
nominal; nominal
A researcher hypothesizes that left-handed subjects will score higher on the Picture Arrangement Test than right-handed subjects. The design is _____, the dependent variable is ______, the independent variable is _______.
non-experimental, scores on the PAT, whether the subjects are right or left handed
The standard error of difference is literally the standard deviation of which important sampling distribution?
sampling distribution of the difference
the total sum of swuares is made up of two major components the
ssw, ssb
The standard error difference is
the SD of the sampling difference
A researcher hypothesizes that a sample of men will score lower than a sample of women on the compassion and empathy scale, an interval-ratio level measure. The statistical test to use would be
the independent samples t-test
if the F statistic is significant in the 1-way ANOVA, the next step to take would be
to reject the null hypothesis and conduct a post-hoc test
Multiple regression analysis should only be run on non-experimental data.
true
Only if the researcher manipulates an independent variable can a study be considered an experiment.
true
Pearsons r of 0 tells you its _____
unrelated.
When all of the points in a scatterplot lie on the regression line, the correlation between the two variables must be
+ 1.0 or - 1.0
When all of the points in a scatterplot lie on the regression line, the correlation between the two variables must be
+1.0 or -1.0
With respect to the "sampling distribution of the mean,"
- mean, median, and mode - the distribution of the means must be normal, even if the actual population distribution from which samples are taken is not
Which of the following, if any, are characteristics of the normal distribution?
-Its mean, median, and mode are all equal -Its form is mesokurtic (the SD = 1/6 of the range) -The areas under the curve are fixed (e.g., 68.26% of the area lies between +1 and -1 SD of the mean)
The null hypothesis for the single-sample t-test is that any difference between the sample mean and the population mean is due to
-chance -random variation -sampling error
Ordinal Scale
-consists of a set of categories that are organized in an ordered sequence -measurements rank observations in terms of size or magnitude -sequence doesn't indicate how much better or worse -Bar Graphs
Nominal Scale
-consists of a set of categories that have different names -measurements label and categorize observations but no quantitative distinctions. -Bar Graphs
Interval Scale
-consists of ordered categories that are all intervals of exactly the same size -the zero point is arbitrary and does not indicate a zero amount of the variable being measured -Histograms
Discrete Variables
-consists of separate, indivisible categories -no values can exist between two neighboring categories
Polygons
-dots about each x-value, dot height indicates frequency -lines drawn to connect dots
Population Variance
-equals the mean of the squared deviations σ^2= SS/N= Σ(X-μ)^2/N -Variance: the average squared distance from the mean
Characteristics of the Sampling Distribution of the Mean
-normal distribution -mean is equal to μ (the population mean) from which these samples drawn -it has a standard deviation, known as the SEM, which is equal to σ (the population standard deviation) divided by the square root of n -is the basis for the Z- Test and the 1- Sample T- Test
Frequency Distribution Tables
-organized tabulation of number of individuals in each category - 'x'= possible scores - 'f''=frequency of each score - 'p'=proportion (f/N) - 'p(100)'=percentage (f/N * 100)
Mean
-population mean= μ -sample mean= M -for skewed distributions the mode will be at the peak, the mean towards the tail, & the median in between the mode and mean. (**Mode Median Mean= Positive Skew .... Mean, Median, Mode= Negative Skew**)
Variability
-provides a quantitative measure of the differences between scores in a distribution -describes distribution whether its clustered or spread out -describes how typical; where it falls relative to the rest of scores -Range, Interquartile/semi-interquartile range, variance/standard deviation
Grouped Frequency Tables
-scores grouped into class intervals -should be about 10 intervals(rows) -Interval width should be simple (ex. 1, 2, 5, 10, 20) -all intervals should have same width
Ratio Scale
-set of ordered categories with equal intervals(interval scale) and a TRUE ZERO -ratios of numbers do reflect ratios of magnitude -Histograms
Central Tendency
-single score must be representative of entire distribution -Mean, Median, Mode
With respect to the "sampling distribution of the mean,"
-the mean, median, and mode must all be equal to the population mean -the distribution of the means must be normal, even if the actual population distribution from which the samples are taken is not
Standard Deviation
-the square root of the variance and provides a measure of the standard, or average, distance from the mean. -SD= σ=√σ^2 -Deviation: distance from the mean= x-μ
Continuous Variables
-there are an infinite number of possible values that fall between any two observed values -divisible into an infinite number of fractional parts -Real Limits: the boundaries of intervals for scores represented on a continuous number line (always half way between adjacent categories) -Upper Real Limit: top of interval -Lower Real Limit: bottom of interval
If we wanted to determine whether a sample of male and female voters differed in their preference for a particular candidate (i.e., for which one would they vote), we would use the
.chi-square test
In any t-test, if the SD ________ our probability of rejecting the null hypothesis increases
.decreases
In any t-test, if the SD ________ our probability of rejecting the null hypothesis _________
.decreases; increases
When we ______ the null hypothesis we are concluding that any difference between mean or between frequencies__________
.fail to reject; is probably due to sampling error
In an independent samples t-test, the obtained (i.e., the calculated) value of t represents
.how far the mean difference is from 0 in standard errors of the difference
The phrase "statistically significant" means that
.the obtained result is unlikely to have come about by chance
We can only use the z-test when we are comparing a sample mean to a known population mean and
.we have the population standard deviation
When all pairs of samples come from a single population , the mean of the distribution of differences assumes what numerical value?
0
With respect to z-scores, for any sample the mean is always ___ and the SD is always
0; 1
With respect to z-scores, for any sample the mean is always ______ and the SD is always
0;1
Characteristics of the normal distribution
1. Its bell shaped 2. Its symmetrical 3. The mean, median, mode are all in the center 4. The 2 tails never touch the horizontal axis 5. Its form is mesokurtic, SD = 1/6 of the range 6. Areas under the curve are fixed
In regression analysis, the intercept is determined by what factors?
1. The mean of Y 2. The mean of X 3. The slope of the regression line
The regression line represents the line that
1. minimizes the residuals when using the value of X to predict the value of Y 2. intersects the Y axis at the point where the X variable equals 0 3. slopes downward when the correlation between X and Y is negative
the standard deviation can..
1. never be negative 2. can be 0 if all the scores are identical 3. can never be more than half the range 4. it functions as the denominator when computing a z-score
With respect to the "sampling distribution of the mean,"
1. the mean, median, and mode must all be equal to the population mean 2. the distribution of the means must be normal, even if the actual population distribution from which the samples are taken is not
The slope of the regression line is determined by
1. the sign of Pearson's r for X and Y 2. The absolute value of Pearson's r for X and Y 3. the standard deviation of both X and Y
To find the percentage of cases falling below a given z Score
1.) If the Z Score is positive, look up the percentage and add 50% 2.) If the Z Score is negative, look up the percentage and subtract 50%
To find the percentage of cases above a given Z Score
1.) If the Z Score is positive, look up the percentage and subtract 50% 2.)If the Z Score is negative, look up the percentage and add 50%
To find the percentage of cases BETWEEN two Z Scores
1.) If the Z-Scores are on opposite sides of the mean, look up the percentages and add them together 2.) If the Z-Scores are on the same side of the mean, look up the percentages and subtract the smaller from the larger
The Mean of the Sampling Distribution of the Mean
1.) It's mean is equal to the μ 2.) It's normal 3.) It has a standard deviation -(σ/sq.n) ~n=sample size ~ this is called the standard error of the mean
With infinite degrees of freedom, what t ration is needed to reject H"v"o at the .05 alpha level?
1.96
With infinite degrees of freedom, what t- ratio is needed to reject Ho at the .05 alpha level?
1.96
How many F's would we need to examine in the 2x4 ANOVA?
3
In a two-way ANOVA how many null hypotheses will there be?
3
In 2x2x3 factorial ANOVA, there are
3 independent variables and 1 dependent variable
A frequency distribution would be mesokurtic if its standard deviation was 8 and its range was A. 16 B. 48 C. 96 D. the range could not be determined based on these data
48
An F ratio of 5 indicates that the variance between the groups is
5 times greater than than the variance within
In a 2x4 factorial ANOVA, how many individual treatment groups are there (what would be the number of groups you would subtract from the number of subjects to determine the df within?)
8
μ sample
>μ, must be less than to reject null, higher than the z
Inferential statistics (such as the independent samples t and chi-square) are referred to as 'inferential' because they are used to draw conclusions about ___ from ___. A. populations; samples B. samples; populations C. hypotheses; theories D. theories; hypotheses
A
Inferential statistics are referred to as 'inferential' because they are used to draw conclusions about ___ from ___. A. populations; samples B. samples; populations C. independent variables; dependent variables D. dependent variables; independent variables
A
Sampling Distribution of the Mean
A frequency distribution of an infinite number of sample means of the size N taken at random (sampling with a replacement) from a population
Z Distribution
A normally distributed set of specially scaled values whose mean is always equal to zero and whose standard deviation must equal 1.00
In a sample of high school runners' times in the 1600 meters, the mode was 4:50, the mean was 4:35, and the median was 4:42. What can we say about the distribution? A. It's negatively skewed B. It's positively skewed C. It's normal (not skewed) D. Nothing - the numbers don't allow us to say anything about the form of the distribution.
A. because the median is greater than the mean
The null hypothesis for the single-sample t-test is that any difference between the sample mean and the population mean is due to
A.chance B.random variation C.sampling error
The regression line represents the line that
A.minimizes the residuals when using the value of X to predict the value of Y B.intersects the Y axis at the point where the X variable equals 0 C.slopes downward when the correlation between X and Y is negative
In an independent samples t-test, the difference between the two sample means can be due to
A.the independent variable B.sampling error
In regression analysis, the intercept is determined by what factors?
A.the mean of Y B.the mean of X C.the slope of the regression line
The slope of the regression line is determined by
A.the sign of Pearson's r for X and Y B.The absolute value of Pearson's r for X and Y C.The standard deviation of both X and Y
Validity
Accurately measures, consistant so often that it becomes valid
If we use an alpha of .01 when testing the null hypothesis, what is the probability of making a Type II error? A. 1% B. 99% C. you cannot tell from the information given D. there is no such thing as a Type II error; only Type I errors can occur when testing the null hypothesis
B
In the t-statistic, the denominator represents variability in the DV due to ____________, while the numerator represents variability in the DV due to _______. A. the indepedent variable and sampling error; everything except the independent variable. B. everything except the independent variable; the independent variable and sampling error. C. both A and B D. neither A nor B
B
The average variation from the mean in a set of measurements in a sample is the conceptual definition of the A. interquartile range B. standard deviation. C. variance. D. standard error of the mean.
B
With respect to z-scores, for any sample the mean is always ___ and the SD is always A. 1; 0 B. 0; 1 C. 100; 10 D. below the median; ½ of the range
B
When we reject the null hypothesis A. we prove the alternate hypothesis (i.e., the research hypothesis) B. we determine that the null hypothesis is unlikely to be true C. we conclude that the results are likely to have come about by chance D. all of the above are true when we reject the null hypothesis
B Feedback: (a) is false because we never 'prove' anything working with sample data to draw conclusions about populations. Since (b) is true, (c) and (d) must necessarily be false.
Given a data set with a standard deviation of 7 and a range of 60, you should conclude that the distribution is A. platykurtic B. leptokurtic C. mesokurtic D. skewed
B because The SD (7) is less than 1/6 of the range (60 /6 = 10), so by definition the distribution is leptokurtic.
Why do we conduct a post-hoc test if we find a significant F in a one-way ANOVA?
Because you don't know which means differ from which other ones when there are more than two of them.
With respect to the "sampling distribution of the mean," A. the mean, median, and mode must all be equal to the population mean B. the distribution of the means must be normal, even if the actual population distribution from which the samples are taken is not C. both A and B are true D. none of the above are true
C
Nominal
Catagorize, mutually exclusive, variable is only labels, so > or < do not apply, no math operations apply, counts and percents only, can only belong to one category, similar to heads or tails
Nominal Data
Choosing between one or the other counts and percentages only Can be numbers but must be from a choice not infinite or decimal points
Which of the following, if any, are characteristics of the normal distribution? A. Its mean, median, and mode are all equal B. Its form is mesokurtic (the SD = 1/6 of the range) C. The areas under the curve are fixed (e.g., 68.26% of the area lies between +1 and -1 SD of the mean) D. Only B and C are true E. A, B, and C are true
E
In linear regression, if the slope is -.25, which of the following is true?
Every unit increase in X will result in a 1/4 unit decrease in Y
Experimental Research
Experiments where the Independent variable(not the sample we're studying) is manipulated and the subject isn't manipulated. Cause can be determined.
The paired t may only test the hypothesis of assosication where as the independent t may test the hypothesis of difference as well.
F
In order to do a )_______ there must be a minimum of ___ different treatment conditions
Factorial annova, 4
A multiple R of .40 means that one of the predictor variables accounts for 16% of the variance in the criterion. T/F
False
Assuming that the mean differences and standard deviations are constant, you are less likely to reject the null hypothesis when using a paired-samples t-test than an independent samples t-test. T/F
False
Every sample measure is assumed to contain bias.
False
For an independent samples t-test and a paired samples t-test with same number of subjects, the degrees of freedom would be the same.
False
For an independent samples t-test and a paired samples t-test with same number of subjects, the degrees of freedom would be the same. T/F
False
If a researcher asks subjects to identify their sexual orientation as either heterosexual, homosexual, or bisexual, sexual orientation is being measured on an ordinal level.
False
If a researcher asks subjects to identify their sexual orientation as either heterosexual, homosexual, or bisexual, sexual orientation is being measured on an ordinal level. True False
False
If a researcher uses the post-facto method and establishes a significant relationship, the possibility of a cause- and -effect relationship must be ruled out.
False
If the correlation between X and Y is zero, the best predictor of the value of Y is the mean of X. T/F
False
If two predictor variables are not significantly correlated with each other, then we should not use both in a multiple R analysis.
False
If two predictor variables are not significantly correlated with each other, then we should not use both in a multiple R analysis. T/F
False
In a 1-way ANOVA, if the sum of squares between remains constant and the number of means being compared increases, you are more likely to find a significant difference among the means.
False
In a 1-way ANOVA, if the sum of squares between remains constant and the number of means being compared increases, you are more likely to find a significant difference among the means. T/F
False
In a factorial ANOVA, a post hot test must be performed when any F is significant T/F
False
In a factorial ANOVA, as the difference between each cell mean and the individual scores within that cell increase, the F ratio will increase T/F
False
In a factorial ANOVA, when neither main effect is significant, the interaction may still be significant.
False
In a multiple regression analysis, all of the predictors must share the same slope value.
False
In a multiple regression analysis, all of the predictors must share the same slope value. T/F
False
In an ANOVA, as the degrees of freedom between increases, the probability of rejecting the null decreases T/F
False
In an ANOVA, when all the main effects are significant, the interaction must also be significant. T/F
False
In any ANOVA, degrees of freedom between must be 1 for main effects and the interaction T/F
False
In correlational research, the independent variable is always manipulated.
False
In experimental research, the dependent variable represents the cause, and the independent variable represents the effect.
False
In experimental research, the dependent variable represents the cause, and the independent variable represents the effect. True False
False
In linear regression, the intercept is the value of X when the value of Y is 0. T/F
False
In linear regression, the mean value of all residuals will be greater for a correlation of -.70 than for a correlation of +.60.
False
In linear regression, the mean value of all residuals will be greater for a correlation of -.70 than for a correlation of +.60. T/F
False
Multiple regression analysis should only be run on non-experimental data. T/F
False
The SSwithin includes variation in the DV due to the effects of the IV. T/F
False
The critical value of F required to reject the null hypothesis increases as the degrees of freedom within increases T/F
False
The null hypothesis for the z test states that the hypothesized population mean is different from the known population mean.
False
The sampling distribution of the difference is the basis from the single sample t-test. T/F
False
The t-test or the z-test can be used if the dependent variable is nominal.
False
The t-test or the z-test can be used if the dependent variable is nominal. True False
False
The term "interaction" refers to an outcome where at least one of the independent variable has an effect on the dependent variable T/F
False
True or False: The alternative hypothesis for the t test always specifies the direction of the difference.
False
True or False: When two sample means differ, no matter by how much, we always reject the null.
False
When r=.40, one variable accounts for 40% of the variability in the other variable T/F
False
When the two sample means differ, no matter by how much, we always reject the null hypothesis. t or f
False
With respect to a factorial ANOVA, if both main effects are significant, the interaction must also be significant.
False
With respect to a factorial ANOVA, if both main effects are significant, the interaction must also be significant. T/F
False
Variabilty
Gives info about how scores differ or vary
Standard Deviation can never be more that ______ the range.
Half
Variability
How much random variation is there in the data that is not due to the independent variable
Leptokurtic Frequency Dist.
If SD<1/6 of the range, it's leptokurtic(tall)
In a one-way ANOVA, as the sum of squares within increases, the probability of accepting the null hypothesis
Increases
When calculating the paried t-ratio, ehat effect does a substantial correlation have on the effect size of the resulting t ratio?
Increases
Post Facto
Independent variable is not manipulated
The branch of statistics wherein estimates of the characteristics of the entire group are made on the basis of having measured a smaller group is called__________.
Inferential
the paried t and the within subjects F should be only used when the data are in the form of at least ________ measures.
Interval
In a sample of high school runners' times in the 1600 meters, the mode was 4:50, the mean was 4:35, and the median was 4:42. What can we say about the distribution?
It's negatively skewed
In a sample of salaries in a company the mean is $60k, the median is $62.5k and the mode is $65k. What can we say about this distribution?
It's negatively skewed
For a given sample size, setting the alpha error at .01 rather than .05 makes it ______ likely to reject the null hypothesis.
Less
With extremely small samples, does the opportunity for rejecting Ho become more or less likely?
Less (bigger samples give smallest SE diff)
For a single sample T ratio, degrees of freedom is equal to...
N-1
As the degrees of Freedom increase (Sample size gets larger), the T- Distributions approach what other important distributions?
Normal or z distributions
Assigned Subject
Not doing an expiriment
Ul = U2
Null Hypothesis.
For the ________________ why do you do n-1 instead of n-2? Why do we use this test?
Paired samples t-test Because they are all the same. (We use this wheb measuring the same subject more than once.)
When both the independent and dependent variables are interval/ratio level, which statistical test should be used?
Pearson's r
Outliers may exert undue influence
Pearsons R
The range of values is not restricted
Pearsons R
Descriptive Statistics
Picture of a population based on sample with respect to a variable, its just the sample chart, simply using that doesn't give us anything
Ordinal Data
Position or rank in a distribution, first, second, third, fourth, fifth, etc. We don't know the exact distinction, grades are ordinal
Descriptive Statistics
Provide a picture of sample characteristics or of a population with respect to the variable, includes Central Tendency, Variability. Does not include Nominal and Ordinal data
When the calculated t is equal or greater than the table value, we ______ the null hypothesis.
Reject
In order to determine the slope you need the
S.D. of x and y
Mesokurtic
SD=1/6R
Platykurtic
SD>1/6 R
An estimate of the standard deviation of the entire distribution of difference.
SEM estimated est SE diff
In an ANOVA design, as the scores in each cell vary from the cell mean by greater amounts, the _______ will _______
SSwithin;increase
A point estimate is a hypothesized parameter based on a _____ value.
Sample
Every point on the abscissa of a sampling distribution of means represents a(n) ____________.
Sample mean
Hypothesis Testing
Sample means; use when we know the population mean, population standard deviation
μ
Sampling Distribution of the Mean
The difference between the sample mean and the population mean (M - m (mue)) is called ____________.
Sampling error
In linear regression, the change in value of Y that occurs with each unit change in X is referred to as the
Slope
If successive random samples are taken from the population, the standard deviation of the resulting distribution of means is called __________.
Standard error of the mean
Any measurement made on a sample is called a(n) ________.
Statistic
Statistic or Parameter? Sample Mean (M)
Statistic
Normal Distribution
Symmetrical, Mean Median and Mode are all equal Only ONE mode No skewness No kurtosis Areas under curve are invariant(unchanging) and we ALWAYS KNOW what percentage of the scores lie above or below a given SD (in frequency distribution its a percent)
If the correlation between X and Y is high and the correlation between X and Z is high, then the correlation between Y and Z must be high
T
A political scientist wants to find out if voters are more likely to prefer a senate candidate who is in favor of strict enforcement of immigration laws. She describes two candidates, each of the same except one supports strict enforcement while the other does not. She then asks a sample of voters who they would vote for. The correct statistical test would be..
The Chi-square test
In estimating the standard error of the mean, we use the sample SD, but then divide it by the square root of N-1 instead of N. Why?
The sample SD is a biased estimate, consistently underestimating the population SD
in estimating the standard error of the mean, we use the sample SD, but then divide it by the square root of N-1 instead of N. Why?
The sample SD is a biased estimate, consistently underestimating the population SD
Population
The set of all possible elements in a collection of group defined by one common characteristics. Example: ALL voting aged people at Rutgers
The slope of the regression line is determined by
The sign of Pearson's r for X and Y, - the absolute value of Pearson's r for X and Y, - the SD of both X and Y
A point estimate is a sample value that is aid to provide the "best" estimate of a single parameter value.
True
Alpa level becomes zero only when both samples reflect different populations.
True
Determining whether the IV is manipulated or assigned indicates whether the research is experimental or post facto.
True
Every sample measure is assumed to contain sampling error.
True
For a given value for the sample's standard deviation, increasing the sample size decreases the estimated standard error of the mean.
True
If a researcher establishes a significant correlation in order to predict college grades on the basis of high-school grades, the high-scool grades are the independent variable.
True
If both main effects were significant in a 2x4 ANOVA, you would have to do a post hoc test for the main effect of the second variable (four levels) T/F
True
If the relationship between 2 ratio level variables follows a U-shaped form, Pearson's r should not be used to test for the relationship. T/F
True
If you were to run an independent samples t-test instead of paired-samples t-test on data from matched pairs where the Pearson's r is >0 (for scores before and after the IV is manipulated), you would be equally likely to reject the null hypothesis T/F
True
In 2x3x4 factorial ANOVA there are 3 IVs, one with 2 levels, one with 3 levels, and one with 4 levels. T/F
True
In a 1-way ANOVA, you cannot have an interaction effect T/F
True
In a 2x2 ANOVA, degrees of freedom-between must be 1 for the main effects and the interaction T/F
True
In a 2x4 ANOVA, there are 3 null hypothesis that must be tested T/F
True
In a factorial ANOVA, when neither main effect is significant, the interaction may still be significant.
True
In a factorial ANOVA, when neither main effect is significant, the interaction may still be significant. T/F
True
In a linear regression analysis, the higher the Pearson's r, the lower the values of the residuals
True
In a linear regression analysis, the higher the Pearson's r, the lower the values of the residuals. T/F
True
In addition to interval-ratio level predictors, nominal predictors can also be included in multiple regression analysis.
True
In addition to interval-ratio level predictors, nominal predictors can also be included in multiple regression analysis. T/F
True
In an ANOVA, both the number of levels of the independent variable and the size of the sample influence the degrees of freedom within.
True
In an ANOVA, both the number of levels of the independent variable and the size of the sample influence the degrees of freedom within. T/F
True
In experimental research, the independent variable always defines the differences in the conditions to which the subjects are exposed.
True
Meta-analysis attempts to combine many research studies and establish an overall effect size for the entire group of studies.
True
Only if the researcher manipulates an independent variable can a study be considered an experiment.
True
Only if the researcher manipulates an independent variable can a study be considered an experiment. True False
True
The F ratio can never be negative T/F
True
The effect size may only be calculated when null hypothesis has been rejected.
True
The formula for determining effect size on the paired-samples t-test is identical to that used for the single-sample t-test T/F
True
The larger the standard deviation of the sample, for a give n, the larger is the estimated standard error of the mean.
True
The mean of the distribution of differences becomes zero only when all pairs of samples represent a single population.
True
The null hypothesis for Pearson's r is r population = 0 T/F
True
The null hypothesis in multiple regression analysis is R (in the population) = 0
True
The null hypothesis in multiple regression analysis is R (in the population) = 0 T/F
True
The reason there is only one number shown for degrees of freedom in any t-test is because the degrees of freedom between must always be 1.
True
The reason there is only one number shown for degrees of freedom in any t-test is because the degrees of freedom between must always be 1. T/F
True
The size of the mean square between in the F statistic is a measure of the effect of the independent variable T/F
True
The standard deviation can be 0. T/F
True
To calculate the z test, the population's parameter values must be known.
True
True or False: A point estimate is a sample value that is said to provide the "best" estimate" of a single parameter value.
True
True or False: Because of sampling error, a point estimate can never be guaranteed to produce the true population parameter.
True
True or False: For a given value for the sample's standard deviation, increasing the sample size decreases the estimated standard error of the mean.
True
True or False: If the null is accepted when it should have been rejected, a Type 2 error has been committed.
True
True or False: The effect size may only be calculated when Ho has been rejected.
True
True or False: The larger the standard deviation of the sample, for a given n, the larger is the estimated standard error of the mean.
True
True or False: The mean of the distribution of the difference becomes zero only when all pairs of samples represent a single population.
True
When an ANOVA results in the rejection of the null hypothesis, the between-group variability must be greater than the within-group variability. T/F
True
When the null hypothesis is rejected even though it should not have been rejected, the _____________ error has been committed.
Type 1 error
Ratio
Variables have a true zero value, represents the absence of property
To establish a "significant difference", what decision must first be made regarding the null hypothesis?
We must reject the null
After obtaining the value of R in a multiple regression analysis, what else must be done?
We need to conduct an F-test to find out if the multiple R is significant
u1 does not equal u2/
We reject the null hypothesis
Dependent Variable
What gets determined or undetermined
If the mean is greater than the median
What's a positive skew?
Frequency Distribution
Where all the variables plot out and how often, the y-axis is ALWAYS the frequency and the x-axis is ALWAYS the variable in question
If there is no population S.D., why cant you use a z-table to determine wether a sample mean is a representitive of a population
You must estimate the SEM and the hypothetical distribution is more platykurtic expcept at n=inf
When all pairs of samples come from a single population, the mean of the distribution of the difference assumes a numerical value?
Zero
In a hypothetical study, a researcher wanted to see if there was any effect on 3 different drugs on whether or not people with asthma experienced improvement (asked whether or not they felt better or not after taking the drug) the appropriate test would be
a chi-square
The F statistical test tells us there is __________
a difference between the four means
Parameter
a value, usually a numerical value, that describes a population
A psychiatrist conducted a research study on people suffering from major depression. He randomly assigned patients to 1 of 4 conditions: no treatment, medication only, cognitive behavioral therapy only, or medication + CBT. The only group that showed improvement was the medication + CBT group. This outcome should be described as
an interaction between medication and CBT
In the chi squared test, the null hypothesis is that
any difference between the frequency observed and frequency expected are due to chance
When doing a t-test, our obtained t-value must ________ the critical value in the table (for the designated degrees of freedom) in order to _________ the null hypothesis.
be equal or greater to or greater than; reject
The denominator in the within-subjects t-test would usually be much smaller than the denominator in the independent samples t-test. Why is that true?
because r>0 for paired samples, but r=0 for independent samples.
Why can we never base conclusions solely on the size of a mean difference or differences in frequences?
because such differences can come about by sampling error no matter how large they are
when an ANOVA results in the rejection of a null hypothesis, then the __ must be larger than that ___
between group, within group
When you reject, the ____ group is larger than the ___ group
between, within
If you get a significant F in a one-way ANOVA what must you do to determine between which specific groups significant differences exist?
conduct a post-hoc test such as Tukey's HSD
Inferential Statistics
consist of techniques that allow us to study samples and then make generalizations about the populations from which they were selected.
As sample size decreases, assuming a t-ratio remained constant, the probability of rejecting the null would ______.
decrease
In a single-sample t-test, as the sample SD increases, the size of the obtained t-value ____, making it ______ likely to reject the null hypothesis.
decrease, less
If we use an alpha of 0.01 as opposed to 0.05, the probability of rejecting the null hypothesis when it is in fact true
decreases
With respect to an independent samples t-test, the sample SDs get larger, the probability or rejecting Ho
decreases
In a single-sample t-test, as the sample SD increases, the size of the obtained t-value ____, making it ______ likely to reject the null hypothesis.
decreases; less
In a single-sample t-test, as the sample SD increases, the size of the obtained t-value ____, making it ______ likely to reject the null hypothesis.
decreases; less since the SD is the main component of the denominator in the ratio, the larger it gets, the lower the t-ratio becomes. You need to equal or exceed the critical value of t (from the table) to reject the null, so a smaller t makes it less likely that you will do so.
the variabce, or mean squarem results from dividing the sum of squares by
degrees of freedom
In a matched sibjects design, the subjects should be equated on some variables that are related to the ___ variable
dependent
Every unit increase in ____, you could have any increase in y,
depending on your variable
In the F statistic, the sum of squares between is influenced by
differences between each group mean and the grand mean
n the F statistic, the sum of squares between is influenced by
differences between each group mean and the grand mean
Control Condition
does not receive experimental condition
Inverse=
downward
In experimental research, the dependent variable represents the ______, and the independent variable represents the _______.
effect;cause In an experiment, the IV is the cause, the DV is the effect. The IV is manipulated first and its effect on the DV is measured afterward.
In the t-statistic, the denominator represents variability in the DV due to ____________, while the numerator represents variability in the DV due to _______.
everything except the independent variable; the independent variable and sampling error
In the t-statistic, the denominator represents variability in the DV due to ____________, while the numerator represents variability in the DV due to _______.
everything except the independent variable; the independent variable and sampling error.
When we ______ the null hypothesis we are concluding that any difference between mean or between frequencies is due to sampling error
fail to reject
If a researcher asks subjects to identify their sexual orientation as either heterosexual, homosexual, or bisexual, sexual orientation is being measured on an ordinal level.
false
In experimental research, the dependent variable represents the cause, and the independent variable represents the effect
false
The t-test or the z-test can be used if the dependent variable is nominal. T/F
false; Both z and t rely on means and SDs, which are not relevant to nominal data, only to interval/ratio level data.
Total variablity results from the accumulated differences between each individual score and
grand mean
between group variablity results from the accumlated differences between each sample mean and
grand mean
The obtained value of any inferential statistic must be ____________ the critical value in order to __________.
greater than; reject the null
When S.D. is greater than the 1/6th of the range we have a ______
greater, 1/6th, platy
the _____ the degrees of freedom for paired samples t-statistic, the ____the likelihood of rejecting the null hypothesis
greater;greater
within group variablity results from the accumulated differences between each indivudal score and
group mean
In an independent samples t-test, the obtained (i.e., the calculated) value of t represents
how far the mean difference is from 0 in standard errors of the difference
In an independent samples t-test, the value of t tells you
how man standard errors of the difference the difference between the sample means is from 0
Operational Definition
identifies a measurement procedure for measuring an external behavior and uses the resulting measurements as a definition and a measurement of a hypothetical construct
Validity
if the measures we're using are measuring the thing we're supposed to be measuring(e.g. if a scale gives the same but incorrect measure every time then it is INvalid)
As σ gets larger, the standard error of the mean would _____ making it _____ likely to reject the null hypothesis. A. increase; less B. decrease; less C. increase; more D. decrease; more
increase;less
Changing the confidence interval from .95 to .99 ___________ the range of mean values within which μ (mue) is assumed to fall.
increases
In a one-way ANOVA, as the sum of squares within increases, the probability of accepting the null hypothesis
increases
With respect to the paired-samples t-test, as the size of the r increases, the t-ratio _____ making it ________ to reject the null hypothesis
increases, more likely
If a researcher wanted to determine if there was a difference between a sample of Democrats and a sample of Republicans in their annual income (measured in dollars) the appropriate inferential statistic to use would be the
independent samples t-test
If a researcher wanted to determine if there was a difference between a sample of Democrats and a sample of Republicans in their annual income (measured in dollars) the appropriate inferential statistic to use would be the...
independent samples t-test
Constructs
internal attributes or characteristics that cannot be directly observed but are useful for describing and explaining behavior
When both the IND and DEP are _________, R is measured of the ______ & ______ of their association.
interva;/ratio level, strength and direction
in pearsons r Both sets of paired scores must be composed of _____ data
interval
To calculate a t ratio, the data must come from which scale of measurement.
interval ratio
a z-test or t-test should be used only when the independent variable is
interval/ratio
Which of the following, if any, are characteristics of the normal distribution?
its mean, median, and mode are equal - its form is mesokurtic - the areas under the curve
The term -2r(SEM1)(SEM2) in the paired samples t-test causes the t-ratio to be ________ than it would if the term were excluded.
larger
when calculated F ratio has a large value it indicates that the vari. between the groups is ______ than the variablity within the groups
larger
Whenb comparing two seperate and unmatched samples, the ____ the sample size, the _____ to reject
larger, more likely
Given a data set with a standard deviation of 7 and a range of 60, you should conclude that the distribution is
leptokurtic
Given a data set with a standard deviation of 7 and a range of 60, you should conclude that the distribution is ________
leptokurtic
For a given sample size, setting the alpha error at .01 rather than .05 makes it _________ likely to reject the null hypothesis.
less
The term -2r(SEM1)(SEM2) in the paired samples t-test causes the t-ratio to be ________ than it would if the term were excluded.
more biased with respect to the population parameter
In a 1-way ANOVA where 3 means are being compared, the null hypothesis would be
mu sample A = mu sample B = mu sample C
With respect to estimating a population mean, compared to a 99% confidence interval, a 95% confidence interval will be
narrower
If the mean is bigger than the median it is
negatively skewed
Observational/ Correlational Method
observing variables in their naturally existing state; cannot be used to determine causality
If class rank were the variable we were using, the level of measurement would be
ordinal
If the range of either scores is in any way restricted, the pearsons R will __________ the degree of
overestimate, correlation
When both the independent and dependent variables are interval/ratio level, which statistical test should be used?
pearsons R
Rank
percentage of individuals with scores at or below a value, when score is identified by percentile rank, its called a percentile
Given a data set with a SD of 15 and a range of 60, you should conclude that the distribution is
platykurtic
Significant correlations always
predicts better than chance
Assuming that a sample size is taken at random from a population, any difference between the sample mean and the population mean is referred to as,
sampling error
When we fail to reject H0, we are concluding that the results (e.g., the difference between means) are due to
sampling error
Interval/Ratio
scale or continuous variables, allows us to compute Standard Deviation (descriptive statistics), represents true quantities (e.g. weight, GPA)how many times you got something
Sample
set of individuals selected from a population, usually intended to represent the population in a research study
Of two hypothetical predictors, age and height, age is significantly correlated with the criterion, speed in 100 meter dash, while height is not. In that case, which of the following should be used
simple linear regression analysis using age as the predictor of speed
When you know the population mean, but the population standard deviation is unknown, and you want to determine if a sample mean is "significantly different" from the population mean, you should use a(n)
single samples t-test
When you know the population mean, but the population standard deviation is unknown, and you want to determine if a sample mean is "significantly different" from the population mean, you should use a(n)
single-sample t-test
In linear regression, the change in value of Y that occurs with each unit change in X is referred to as the
slope
When calucating the paired-t ratio, what effect does a substantial correlation have on the size of the estimated standard error of difference?`
smaller
As the degrees of freedom gets ____ you need a ___ value
smaller, bigger
Demonator will be _______, if the T is larger. It makes it _______ to reject the null
smaller, likely
The average variation from the mean in a set of measurements in a sample is the conceptual definition of the
standard deviation
The sampling distribution of the mean has a standard deviation referred to as the
standard error of the mean
Positive Skew
tail on right side, peak on left
The standard error of the difference is
the SD of the sampling distribution of the difference
the standard error of the mean is
the SD of the sampling distribution of the mean
A researcher conducts a one-way ANOVA and reports F(4,95) = 13.82, p<.01. The 4 represents ______ and the 95 represents ______.
the df between; the df within
The size of the chi-square statistic depends on
the differences between frequency observed and frequency expected by chance in each cell
In an experiment, the numerator in the F statistic is a measure of
the effect of the independent variable on the dependent variable
In an experiment, the numerator in the F statistic is a measure of
the effect of the individual on the dependent variable
In an independent samples t-test, the difference between the two sample means can be due to
the independent variable sampling error
With respect to experimental data, the NUMERATOR in the t-ratio represents the variation in the dependent variable due to
the independent variable and sampling error
Sampling Error
the naturally occurring discrepancy, or error, that exists between a sample statistic and the corresponding population parameter.
Population
the set of all the individuals of interest in a particular study; vary in size
In any t-test what influences whether or not we reject the null?
the size of the difference between means the sample size the sample SD
In an F-test, we use the SS within, which represents
the squared amount of variance between each individual score and the mean of the group (the cell) in which that individual is located
The sampling distribution of the mean has a standard deviation referred to as the
the standard error of the mean
With Factorial Anova, you only do the tukey test when you have _____ means, and if you ____
three, reject
If the F statistic is significant in the 1-way ANOVA, the next step to take would be
to reject the null hypothesis and conduct a post-hoc test
Only if the researcher manipulates an independent variable can a study be considered an experiment. T/F
true
With respect to the t-table, with an extremely large sample size (N=infinity) the critical values of t become virtually identical to those in the Z table (e.g. 1.96 for a=.05, 2-tailed) T/F
true
Using an alpha of .01 instead of .05
will decrease the effect size statistic
Slope in the line represents hoq many changes in ___ and ___
y & x
