Stats Final Exam
Fill in the missing values for A and B in this frequency distribution table: Intervals Frequency 6.0-6.6 12 5.3-5.9 7 4.6-5.2 B 3.9-4.5 10 A-3.8 8 50
A = 3.2, B = 13
Post hoc tests are computed
Following a significant ANOVA test to make pairwise comparisons.
A scientist finds two results. Result #1 is that higher education is associated with a larger annual income. Result #2 is that fewer calories consumed is associated with less visits to the doctor. How would you characterize these two results?
Both results show a positive correlation.
Which measure of effect size is most commonly reported with a t test?
Cohen's d
Suppose that a researcher selects a sample of participants from a population. If the shape of the distribution in this population is positively skewed, then what is the shape of the sampling distribution of sample means?
approximately normally distributed
What terms refer to each of the following measures, respectively: mean, median, and mode.
average, middle, and most
Based on the effect size conventions, d = 0.60 is a
medium effect size
Correlations can be depicted in a graph called a _______________
scatter plot
A researcher sampled 16 couples and measured the mean difference in their marital satisfaction. Each couple was paired and the differences in their ratings (on a 7-point scale) were taken. If the mean difference in satisfaction ratings for this sample was 1.8±2.0 (), then what is the decision at a .05 level of significance?
Satisfaction ratings significantly differ, t(15) = 3.60.
EXTRA CREDIT. 2 PTS. What is the description of SS (Sum of squares) in words? That is, what does it stand for?
Sum of squared deviations of scores from the mean.
A researcher conducts two t tests. Test 1 is a one-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a one-tailed test with a larger sample size at a .05 level of significance. What do you know about the critical values for each test?
Test 2 is associated with smaller critical values.
The sign test is used as a nonparametric alternative to which parametric test?
both A and C
The sample variance is an unbiased estimator of the population variance
both B and C
Which of the following is recorded using a chi-square goodness-of-fit test and a chi-square test for independence?
both B and C
We convert r to a chi-square statistic for which of the following correlation tests?
phi
Each of the following is an example of quantitative data, except
political affiliation
A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their four-year degree. College debt is on what scale of measurement?
ratio
The correlation coefficient measures the extent to which changes in one factor are _______ in a second factor.
related to changes
To construct a pie chart, first distribute the data as
relative percentages
A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will____ (Hint: Calculate the mean first!)
remain the same
A researcher obtains z = 1.45 for a one-sample z test. What is the decision for this test at a .05 level of significance?
to retain the null hypothesis
Regardless of the number of scores in a distribution, the range only includes ___ score(s) in its calculation.
two
Suppose that the probability that any child of alcoholic parents becomes alcoholic is p = .16. Assuming independent outcomes, the probability that two children of alcoholic parents will be alcoholic equals
.03
A researcher computes a 4 × 6 chi-square test for independence with a sample of 120 participants, with X^2 = 14.79. What is the effect size for this result?
.20
What values are distributed along the x-axis for a sampling distribution of the sample mean?
sample means
Hypothesis testing is also called
significance testing
A researcher reports the following results for a chi-square test: (1) = 5.386, p < .05 (V = 0.224). If this test were a test for independence, then how many groups (cells) were observed?
4
The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many participants were observed in this study?
40
When computing a chi-square goodness-of-fit test, the frequency expected in a given cell should never be less than
Five
The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating
a stronger relationship between two factors
An example of a binomial variable includes
sex (male, female)
Bar charts are a lot like histograms, except
the bars displayed in the graph do not touch
Measures of variability can range in value from
0 to + ∞
Which of the following is NOT a characteristic of probability?
Probability is most useful for describing fixed events.
A researcher conducts a chi-square goodness-of-fit test in which k = 3 and = 4.32. What is the decision for this test at a .05 level of significance?
Retain the null hypothesis.
Which design allows you to test an interaction effect?
a two-way ANOVA
The one-sample z test is a hypothesis test used to test hypotheses
concerning a single population with a known variance
When reporting the results of a one-sample z test using APA format, the ________ do/does not need to be reported.
critical values
A Pearson r statistic would be the proper statistic to use to test the relationship between
height and weight
Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes
inferential statistics
(EXTRA CREDIT) Using a two-way between-subjects ANOVA with Factor A (Gender: male, female) and Factor B (Type of employment: blue collar, white collar), a researcher found that salary for men and women significantly varied across the levels of the second factor (type of employment). That is, the effect of gender depended on type of employment. In this study, the researcher found a significant
interaction
A news poll showed that voters had no preference for any of the three candidates. In this example, the probability of a vote for, say, Candidate A equals
1/3
A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus. The researcher computes SS = 1,000. Assuming that a sample of 11 participants was observed in this study, what is the standard deviation for these data?
10 seconds
A researcher selects a sample of size 4 from a population of size 6. How many possible samples of this size can be selected using experimental sampling?
15
A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data?
16
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSE ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122
2
A researcher selects a sample of 80 people and records the frequency of participants choosing a low, moderate, or high calorie dessert in a buffet. What are the degrees of freedom for this chi-square goodness-of-fit test?
2
When SS = 100 and N = 25, the population standard deviation is equal to __
2
A researcher finds that 12% of participants make between 3-5 visits to a physician each year. What are the real limits for this interval?
2.5-5.5
The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding percentages in each interval listed from the top down. Intervals Frequency 44-46 6 41-43 4 38-40 5 35-37 10 32-34 5 30
20%, 13%, 17%, 33%, 17%
A researcher reports that the probability of a college student living on campus is p = .38. If a small local college has 2,000 students enrolled, then what is the standard deviation of college students living on campus? Hint: This is a binomial probability distribution.
21.7 students
How many possible samples of size 2 can be selected from a population of 5 using theoretical sampling?
25
(EXTRA CREDIT) A researcher assigned participants (n = 8 per group) to read vignettes describing a person engaging in either a helpful, hurtful, or neutral act. Different participants were assigned to each group and asked to rate how positively they viewed the person described in the vignette. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance?
3.47
A researcher selects a sample of 6 males and 11 females. She asks participants to rate the likelihood they would do female-stereotyped jobs (such as nursing or school teaching) on a scale from 1 = not likely at all to 5 = very likely. Men indicated that they would be less likely to do these jobs (M = 2.1) compared with women (M = 4.3). What is the weighted mean for this entire sample of 17 participants?
3.5
A researcher computes a 2 × 2 chi-square test for independence. What is the critical value for this test at a .05 level of significance?
3.84
A researcher selects a sample of 32 participants who are assigned to participate in a study with one group. What are the degrees of freedom for this test?
31
A researcher selects a sample of 100 participants from a population with a mean of 38 and a standard deviation of 20. About 68% of the sample means in this sampling distribution should be between a sample mean of
36 and 40
A researcher determines that the probability of missing class among students at a local school is p = .16. Assuming that the school has 300 students enrolled, how many students can we expect to miss class on a given day? Hint: This is a binomial probability distribution.
48 students
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the total df? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122
49
A researcher computes a 2 × 3 chi-square test for independence. What is the critical value for this test at a .05 level of significance?
5.99
Which of the following will decrease the value of the mean?
adding a score below the mean
Computing a one-sample t test is appropriate when
all of the above
For the related samples t test, assuming that all other values remain constant, then as samples size increases,
all of the above
The assumptions for performing Pearson r test are
all of the above
The "empirical rule" states that
both b and c
The mean of the sampling distribution of sample means is
equal to the population mean
Which of the following is not one of the four steps to hypothesis testing?
evaluate the plan
A therapist observes that spouses are more likely to forgive their partners for lying to them if they find out the truth from their spouse and not a third party. In this example, the dependent variable is
forgiveness
The Friedman test is used as a nonparametric alternative to which parametric test?
one-way within-subjects ANOVA
A chi-square goodness-of-fit test shows that the frequencies observed fit well with those that were expected. Hence, the decision was to
retain the null hypothesis
A researcher records the time it takes to complete a memory task in a sample of 25 participants. He finds that the average participant completed the test in 43 seconds. The average time to complete this task is called a(n)
sample statistic
The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown.
sample variance; population variance
What values are distributed along the x-axis for a sampling distribution of the sample variance?
sample variances
Researchers measure data in a ________ to learn more about individuals in the larger _______ of interest.
sample; population
For the experimental sampling strategy,
sampling is without replacement
The normal distribution is symmetrical, which means that
scores above the mean are distributed the same as scores below the mean
A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA?
(2, 42)
What is the z score for scores in the bottom 5%?
-1.645
The mean crying time of infants during naptime at a local preschool is 12 minutes (that's the population mean). The school implements a new naptime routine in a sample of 25 infants and records an average crying time of 8±4.6 (M±SD) minutes. Calculate t.
-4.35
A researcher measures the following correlation between number of years of education and life satisfaction: r = +0.08. What is the value of the coefficient of determination?
.01
What is the typical level of significance for a hypothesis test in behavioral research?
.05
A researcher records the following data for the number of bids made on a sample of items sold at an auction. Based on the table, what was the probability that an item had 7 bids made on it? Number of Bids Frequencies 3 5 4 12 5 7 6 6 7 10
.25
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making more than five errors.
.29
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at most two errors.
.43
A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year. Hence, the probability of her patients showing significant improvement in mental health is
.50
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at least three errors.
.57
A researcher measures the relationship between two variables, X and Y. If = 340 and SSxSSy= 320,000, then what is the value of the correlation coefficient?
.60
In a game, the probability of winning money is p = .16, the probability of losing money is p = .54, and the probability of breaking even is p = .30. What is the probability of winning or losing money in this game?
.70
The probability of making zero to two errors per 1,000 keystrokes is 0.43, and the probability of making three to five errors per 1,000 keystrokes is 0.28. Find the probability (per 1,000 keystrokes) associated with making at most five errors.
.71
The standard normal distribution is normally distributed with a mean of ____ and a variance of ____.
0; 1
What is the z score for scores in the top 2.5%?
1.96
A researcher measures the relationship between narcissism and willingness to help. If SSxy = 240, SSx = 320, and SSy = 410, then what is the value of the correlation coefficient?
0.66
A researcher records the frequency of participants selecting one of four new slogans for an advertising campaign. If it was expected that among 200 people polled there would be no preference for any one slogan, then what was the expected frequency for each slogan.
50 people
EXTRA CREDIT. A psychologist tests whether cravings for heroin and relapse are independent. The following table lists the observed frequencies, with the expected frequencies listed in parentheses. Calculate chi-square for these data. Chi-square = Relapse Yes No Cravings Yes 22 (17.07) 11 (15.93) 33 No 8 (12.93) 17 (12.07) 25 30 28 N=58
6.84
A normal distribution has a mean equal to 53. What is the standard deviation of this normal distribution if 2.5% of the proportion under the curve lies to the right of x = 66.72? (Round your answer to two decimal places)
7.00
A researcher computes a 3 × 5 chi-square test for independence. What are the degrees of freedom for this test?
8
A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSBG ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122
8
What is the percentile point at the 80th percentile in the following distribution? Frequency Percentile Rank 9-11 100% 6-8 80% 3-5 40% 0
8
If the standard deviation of a probability distribution is 9, then the variance is
81
A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school. In his study, he found that the sound was 80±6 (M±SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion?
95% of classes were between 68 and 92 decibels.
A researcher selects a sample of 36 dog owners and measures their responsiveness to two types of pictures: one depicting the humane treatment of dogs and one depicting the inhumane treatment of dogs. The researcher finds that responsiveness significantly differed, t = 3.243. Use eta-squared to compute the proportion of variance for this result.
= 0.23
Which of the following measures of effect size can be reported with a 3 × 4 chi-square test for independence?
Cramer's V
________ allows researchers to describe (1) how far mean scores have shifted in the population, or (2) the percentage of variance that can be explained by a given variable.
Effect size
Which of the following is an assumption for the two-independent sample t test, but not the one-sample t test?
Equal variances
A chi-square goodness-of-fit test leads to a decision to retain the null hypothesis. Which of the following correctly explains this decision?
Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
What does it mean to say that the sample mean is an unbiased estimator of the population mean?
If we select a sample at random, then on average we can expect the sample mean to equal the population mean.
EXTRA CREDIT!! What is the central limit theorem?
It explains that a sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population.
Which of the following is a key assumption for a chi-square goodness-of-fit test?
The observed frequencies are independently recorded in each cell.
A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of these data?
It is very small (close to 0) because scores are approximately the same.
Imagine you are a journal editor. A researcher reports means and standard deviations for groups for a study that required running a chi-square test. Is there a problem? If so, what is it?
It's not meaningful to calculate means and SDs for chi-square data because the data represent frequency counts.
A researcher measures the following correlation between cost of produce and number of units sold. Which description best explains the relationship between these two factors?
Less expensive produce is associated with an increased number of units sold.
A researcher reports that the size of an effect in some population is d = 0.88. Which of the following is an appropriate interpretation for d?
Mean scores shifted 0.88 standard deviations in the population.
A researcher measures the amount of coffee consumed by college students while studying during the final exam week. In her study, she found that students drink 2.3±0.8 (M±SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion?
Most students drink between 1.5 and 3.1 cups of coffee per study session.
The size of a population is symbolized as ________, whereas the size of a sample is symbolized as ________.
N; n
Is a one-sample z test reported differently for one-tailed and two-tailed tests?
No, the same values are reported.
A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20) or female (n = 12). The mean likability rating in each group was 4.0. If the null hypothesis is that there is no difference in likability ratings, then do likability ratings differ at a .05 level of significance?
No, this result is not significant, t(30) = 0.
What is a key distinction between parametric tests and nonparametric tests in terms of scales of measurement?
Parametric tests are used for interval and ratio data, whereas nonparametric tests are used for nominal and ordinal data.
EXTRA CREDIT. The formula for the Spearman correlation coefficient was derived from the formula for___________________________________________________________
Pearson r
A researcher measures the correlation of the time it takes participants to complete two tasks purported to measure the same cognitive skill. Participant times are converted to ranks from fastest to slowest. If ED2 = 165 and n = 20, then what is the decision for this correlation test?
Reject the null hypothesis because the calculated value exceeds the critical value.
A researcher selects two samples of 64 participants each. In the first sample the population mean was 10 and the variance was 16. In this second sample, the population mean was 25 and the variance was 9. Which sample will be associated with a larger standard error of the mean?
Sample 1
A researcher measures the number of trials it takes two samples of participants to master a new task. In both samples, SS = 240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. Which sample is associated with the largest variance?
Sample A
State the problem with this simple frequency distribution. Intervals Frequency 8-10 4 6-8 7 4-6 3 2-4 6 0-2 9
The class intervals overlap.
Using APA format, which value is typically given in parentheses when reporting the results for a t test?
The degrees of freedom.
What is the definition of "power" in statistics usage?
The likelihood of rejecting a false null hypothesis
A researcher measures the following correlation between cups of coffee consumed daily and daily work schedule. Which description best explains the relationship between these two factors?
The more a person works, the more coffee he or she tends to drink.
Which of the following statements regarding the null hypothesis is true?
The null hypothesis always makes statements about a population parameter.
Which proportion is largest in a z distribution?
The proportion of area between z = +1 and z = -1.
A researcher reports that "the average shopper in the sample (n = 12) purchased $65.00 worth of items (μ = $65.00) during a busy shopping day." What mistake was made is this citation?
The sample mean is written using the wrong notation.
Which of the following is the best explanation for why the standard deviation is almost always reported with the mean?
The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation.
A professor grades 120 research papers and reports that the average score was an 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%?
The sum of the differences is equal to zero.
State whether the first area is bigger, the second area is bigger, or the two areas are equal: the area to the left of z = 0.80, or the area to the right of z = -0.80.
The two areas are the same.
EXTRA CREDIT!! A researcher randomly selects a sample of athletes and reports that their average score on a health and fitness scale is 23. Based on the characteristics of the sample mean, what does this say about the mean in the population?
We expect that the population mean is equal to 23 because the sample mean is an unbiased estimator of the population mean.
An unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables is called
a confound variable
A researcher wants to determine how many participants will take less than 24 seconds to complete a cognitive performance task. If he constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer his question?
a cumulative frequency distribution from the bottom up
The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that
all of the above
The t distribution is similar to the z distribution except
all of the above
Which of the following is an assumption for computing any type of independent sample t test?
all of the above
Which of the following is an example of a parametric test?
all of the above
Which of the following is true about the computational formula for variance?
all of the above
The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________.
alpha; beta
The numerator of the correlation coefficient measures the extent to which two variables
both A and C
Which of the following is a statistical procedure used to test hypotheses about the discrepancy between the observed and expected frequencies in two or more nominal categories?
chi-square test
EXTRA CREDIT. 2 PTS. Qualitative data varies by ________; quantitative data varies by ________.
class; amount
Bayes' theorem is often applied to a variety of ________ probability situations, including those related to statistical inference.
conditional
When the probability of one outcome changes depending on the occurrence of a second outcome, these outcomes are referred to as
conditional
A researcher runs an independent groups design and reports that the mean difference in response time to an auditory versus a visual cue is 0.83 seconds, with a pooled sample variance equal to 2.45. What is the effect size for this test using estimated Cohen's d?
d = 0.53
The use of tables and graphs to summarize data is an example of
descriptive statistics
The scale of measurement a researcher uses
determines the type of inferential statistics that can be done
A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this figure represent?
df = 23; it represents the number of scores that are free to vary in a sample.
Another name for a binomial variable is a
dichotomous variable
The test statistic for a related samples t test makes tests concerning a single sample of
difference scores
Computing a one-way between-subjects ANOVA is appropriate when
different participants are observed one time in each of two or more groups for one factor
Many nonparametric tests are called ________ because they make no assumptions regarding the shape of the distribution in the population.
distribution-free tests
The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as
homoscedasticity
A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called
hypothesis testing
Each of the following is an advantage for using the related samples design, except
it increases the variability measured in a study
In the stem-and-leaf display, each number to the right of the vertical line is referred to as a ________; the numbers to the left of the vertical line are called the ________.
leaf; stem
A researcher selects a sample of 16 participants from a population with a variance of 4. What is the standard error of the mean?
less than 1
A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data?
mean
The ________ is the middle value in a distribution of scores that are listed in numeric order.
median
Which rule states that when two outcomes are independent, the probability that these outcomes occur together is the product of their individual probabilities?
multiplicative rule
A correlation coefficient can ______ demonstrate cause.
never
An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college?
nominal
State the four scales of measurement in order from least informative to most informative.
nominal, ordinal, interval, ratio
A researcher conducts two chi-square tests. The 2 × 2 chi-square was χ2 = 3.82. The 2 × 3 chi-square was χ2 = 5.02. Which chi-square test resulted in a decision to reject the null hypothesis at a .05 level of significance?
none; both chi-square tests result in a decision to retain the null hypothesis
The following distribution most closely approximates a
normal distribution
A researcher reports a significant mean difference in a given population. If she computes both eta-squared and omega-squared to measure the effect size, then which estimate will be the most conservative?
omega-squared
The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where
one is continuous, and one is dichotomous
One difference between a repeated measures design and a matched samples design is that
only one design involves observing the same participants in each group
The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ________ variables.
ordinal
The probability of a college student being employed is p = .35. The probability of a student being employed and dropping out of college is p = .20. Hence, the probability of a student dropping out of college, given that he or she is employed, is
p=.57
A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a
percentile rank
Regardless of the shape of the distribution in the population, the sampling distribution of sample variances approximates a
positively skewed distribution
The proportion or fraction of times an outcome is likely to occur is referred to as
probability
Which of the following indicates the strongest correlation?
r = -0.90
A researcher records the time it takes (in seconds) for participants to respond (by pressing a key) to a familiar versus an unfamiliar word flashed onto a computer screen. In this study, the difference in response time for each participant is compared. The type of design described here is called a
repeated measures design
A type of related samples design in which participants are observed more than once is called a
repeated measures design
A researcher observes a correlation of values from 2 to 10 points and draws conclusions about the full range of values in the population from 0 to 21 points. Which limitation for correctly interpreting a correlation coefficient did the researcher violate?
restriction of range
Compared to the two-independent sample t test, the related samples design decreases
standard error
The correlation coefficient is used to measure the ________ and ________ of the linear relationship between two factors.
strength; direction
The ________ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis.
t statistic
Which of the following summarizes a t test that was significant and associated with a large effect size?
t(12) = 2.95, p < .05, d = .82
Scores far from the mean are located in the ________ of a normal distribution.
tails
What is the implication for the tails of a normal distribution being asymptotic?
that extreme scores are possible in a normal distribution
Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean?
that the variance is equal in each population from which samples are selected
A researcher records 17 scores. What is the median position of these scores?
the 9th score in numeric order
A researcher records 52 scores. What is the median position of these scores?
the average of the 26th and 27th scores in numeric order
Which of the following would not be reported for a correlation?
the critical values for each test
As a general rule, the larger the degrees of freedom for a chi-square test,
the larger the critical value will be
Each of the following statements are true, except that
the larger the sample size, the larger the standard error
Increasing the number of observations or samples in a study will decrease the standard error (standard error of the mean). This is known as
the law of large numbers
Which of the following best describes an independent variable?
the manipulated variable
Which of the following best describes a dependent variable?
the measured behavior
For an analysis of variance, the term "one-way" refers to
the number of factors in the design
The appropriate correlation coefficient for measuring for the direction and strength of the linear relationship between two dichotomous variables is
the phi correlation coefficient
The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between one continuous and one dichotomous variable is
the point-biserial correlation coefficient
To compute a two-independent sample t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test?
the pooled population variance
Two outcomes are said to be mutually exclusive when
the probability of the two outcomes occurring together is equal to zero (p = 0)
You are interested in measuring the construct, reinforcement. Which of the following measures for this construct is quantitative and continuous?
the size of a reward in grams
If the expected frequencies equal to observed frequencies for a chi-square test for independence, what do we conclude?
the test statistic value is equal to 0
Each of the following is an example of a binomial distribution, except
the time it takes to complete a driving test
The normal distribution has all of the following characteristics, except
the total area under the curve is greater than 1.0
How is the standard error of the mean typically reported in a graph?
using error bars
When would a researcher calculate a population mean?
when data are measured for all members of a population
Each deviation in the numerator for variance is squared because
without squaring each deviation, the solution for SS would be zero
A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example?
yes
The unit of measurement distributed along the x-axis of a standard normal distribution is referred to as a
z score
State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20).
±2.086
