Behavioral Statistics (Final Exam)
what is the typical level of significance for a hypothesis test in behavioral research?
.05
How many F ratios are calculated in a two-way analysis of variance?
3
If a research article presented the results of an analysis of variance as, "F (2, 38) = 3.60, p < .05," then how many groups were there in the study?
3
In an analysis of variance with a within-group variance estimate of 8.5 and a between-groups variance estimate of 5.3, the F ratio is
5.3/ 8.5= 0.62
If all the possible random samples with n= 36 scores are selected from a normal population with mean=80 and mean= 18, and the mean is calculated for each sample, then what is the average of all the samples means?
80
For a research study comparing attitude scores for males and females, participant gender is an example of what kind of variable?
A quasi-independent variable
The probability of committing a Type 1 error is states by.......; the probability of committing a Type 2 error is states by......
Alpha; Beta
To compute a two-independent-sample t test, a researcher had to know many values. which of the following is NOT a value that the researcher must know to compute this test? A) the pooled sample variance B) the pooled population Variance C) the sample size for both samples D the sample mean for both samples
B
which of the following is not one of the four steps to hypothesis testings? A) state the hypotheses B) identify hypothetical data C) set the criteria for a decision D) compute the test statistics
B
Which of the following describes the definitional formula for variance?
It is stated in terms of how variance is defined. It is computed using SS in the numerator. It is a measure of the average squared distance that scores deviate from their mean.
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.
Which of the following is NOT a characteristic of probability?
Probability is most useful for describing fixed event
Two researchers (A and B) compute a one-sample t test. For both tests, the mean difference between the sample and value stated in the null hypothesis is 5, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis?
Researcher B
The fact that the sum of the differences of scores from their mean is zero best illustrates that ______.
The mean is the "balance point" of a distribution.
Why is 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 researcher records the number of traffic tickets issued in each county along the New York State thruway. If the results are presented in a frequency distribution graph, what kind of graph should be used? -bar graph -histogram -polygon -either histogram or polygon
a bar graph
which of the following of factors will produce the smallest value for the standard error of the mean?
a large sample and a small standard deviation
A researcher visits a population of 1,200 local residents to determine the proportion of local residents who support a new smoking ban. In this case, the sample space is
equal to the population of 1,200 local residents
A key difference between a t statistic and a z statistic is that the standard error is _________ to compute a t statistic
estimated
A researcher reports a significant effect with t(14) = 3.24. compute eta squared for this result
eta squared= 0.43 (large effect size)
Three research methods common to research in the behavioral sciences are
experimental, quasi-experimental, and correlation
What are 3 hypothesis tests we need to conduct for a factorial ANOVA?
factor A, factor B, and interaction effect
The t distribution is similar to the z distribution, except
it is associated with greater variability it is characterized by thicker tails with compared to the z distribution it is associated with scores being more likely in the tails of the distribution
What happens to population mean as sample size increases?
it stays constant
An interaction effect can be identified by
looking at the pattern of cell means
A researcher reports that the size of an effect in some population is d=0.88. which of the following is an appropriate interpretation of d?
mean scores shifted 0.88 standard deviations in the population
In a factorial analysis of variance, you reject the null hypothesis when the F ratio is
much larger than 1
A researcher is curious about the average monthly cell phone bill for high school students in the state of Florida. If this average could be obtained, it would be an example of a _______
parameter
A population of scores has a mean of μ = 26, a median of 23, and a mode of 22. What is the most likely shape for the population distribution?
positively skewed
_____ data describe numeric aspects of phenomena; whereas _____ data describe non-numeric aspects of data.
quantitative; qualitative
To determine the interval width, we divide the _______ by the number of intervals.
real range
Two researchers (A and B) compute a one-sample t test. For both tests, the mean difference between the sample and value stated in the null hypothesis is 5, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis?
researcher A
A distribution of z scores is distributed in what type of unit of measurement?
standard deviation units
For an experiment comparing two methods for teaching social skills training to autistic children, the independent variable is ________ and the dependent variable is _________.
teaching methods (IV) social skills learned (DV)
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
What term is used to identify the mean of the distribution of sample means?
the expected value of M
In a normal distribution, the mean can take on any value and the standard deviation can take on any positive value. Therefore,
there are an infinite number of possible normal distributions
A researcher computes a test statistic and finds that the p value for this test is .03. what does this result mean
there is a 3% likelihood of obtaining the test statistic value, if the null were true
In an analysis of variance, if the null hypothesis is true, then
there is less variance among means of samples than if the null hypothesis were not true
A professor gives an exam in which the mean score is 78 points. she give another exam to test whether or not scores change. In this example, the null hypothesis is
u=78
How many separate samples would be needed for a two-factor, independent-measures research study with 3 levels of factor A and 3 levels of factor B?
9
all of the following are advantages of factorial designs except... A) they automatically provide an indicator of effect size for the measured variables B)they are more efficient C) the combined influences of variable can be studied
A
which of the following statements regarding the null hypothesis is true? A) the null hypothesis always makes statements about a population parameter B) a decision in hypothesis testing is made about the alternative hypothesis, not the null hypothesis C)the null hypothesis is the only hypothesis states in hypothesis testing D) all of these
A
what is an interaction effect?
It tests the effect of one independent variable at each level of another independent variable in an ANOVA.
A researcher reports the following result for a one-sample z test at a .05 level of significance: z=1.88, p=.06, d=0.25. Is this result significant?
No, the decision is to retain the null hypothesis
If a frequency distribution is shown in a bar graph, what scale was used to measure the scores?
Nominal or ordinal scale
if an experimenter "crosses Intelligence with Attractiveness" in a factorial design in which intelligence has three levels (high, medium, and low) and attractiveness has two levels (high and low), the study will
be a 3 x 2 analysis of variance
It is most appropriate to report effect size with a significant result. Why is it generally inappropriate to report effect size with non significant results
because insignificant results indicate that an effect size is also not significant
scores close to the mean are located in the ________ of a normal distribution.
body
An analysis of variance differs from a t test for independent means in that an analysis of variance
can be used to compare three of more groups, while a t test for independent means cannot be used to compare more than two groups
A researcher reports that the mean time it takes to complete an experimental test is 1.4 +- 8.0 (M+- SD). if the null hypothesis was that the mean equals 1.0, then what is the effect size for this test using estimated cohen's d?
d= 0.05; small effect size
suppose that a deck of 40 cards has 12 yellow- colored cards and 28 blue-colored cards. In this same deck of cards, 28 cards are numbered and 12 cards have shapes on them. what is the probability that one card chosen at random is numbered?
d=.70
The use of tables and graphs to summarize data is an example of _________ statistics.
descriptive statistics.
A researcher conducts a study, but has low power to detect an effect. Which of the following is one way in which the research can increase power?
increase the sample size
Procedures that allow researches to infer or generalize observations made with samples to the larger population from which they were selected best describes ______
inferential statistics
In a factorial analysis of variance, the effect size for each main and interaction effect
is different fro each row, column, and interaction effect.
A researcher records a hospital's admission rates for several diseases. She finds that coronary heart disease and lung cancer had the highest frequencies of admission. Which measure of central tendency did this researcher use to describe these data? -mean -median -mode -range
mode
The variance and standard deviation can never be
negative
The students in a psychology class seemed to think that the midterm exam was very easy. If they were correct, what is the most likely shape for the distribution of exam scores?
negatively skewed
Is a one-sample t test reported differently for one-tailed and two-tailed
no, the same values are reported
an interaction effect in a two-way factorial design
occurs when the influence of one variable that divides the groups changes according to the level of the other variable that divides the group
In a distribution with positive skew, scores with the highest frequencies are ______ .
on the left side of the distribution
In a two-way factorial design, there can be
one interaction and two main effects
A researcher selects a sample of 36 students from a school population with a mean IQ of 100 and a standard deviation of 12. She determines that the mean IQ in this sample is 104. Assuming she computes a one-sample z test at a .05 level of significance, what is the decision for a two-tailed test?
reject the null hypothesis; IQ scores in this sample are significantly higher than those in the population
A researcher is interested in the sleeping habits of American college students. A group of 50 students is interviewed and the researcher finds that these students sleep an average of 6.7 hours per day. For this study, the 50 students are an example of a ______ .
sample
Which of the following is an example of a discrete variable? -the age of each student in a psychology class -the biological sex of each student in a psychology class -the amount of time needed to solve a problem -the amount of weight gained for each first year student at a university
the biological sex of each student in a psychology class
In a two-way analysis of variance, the degrees of freedom for each main effect are
the number of levels of the variable minus 1
As a requirement for t test, researchers compute any type of t test with samples selected from population in which
the population variance is unknown
Researcher state a level of significance in terms of an alpha level. the alpha level indicates
the probability of committing a Type 1 error the probability of incorrectly rejecting the null hypothesis the probability value for the rejection region
experimental research is typically conducted using a sampling strategy in which
the same participant can never be selected twice in the same sample
What term is used to identify the standard deviation of the distribution of sample means?
the standard error of M
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
A population distribution has mean of 6. What position in this identified by an individual value with a z-score of z= +2.00?
twelve points above the mean
A professor compares final exam scores in his psychology class to final exam grades in another comparable professor's class. Assuming that the population variance of exam scores is unknown, what type of t test is appropriate for analyzing differences between these classes?
two-independent-sample t test
A therapist has a goal to reduce the mean number of patient symptoms expressed for a particular disorder to two symptoms per day. Following therapy, she determines that the z score for 2 symptoms per day is 0. Assuming the data are normally distributed, did she reach her goal?
yes, because a z score of 0 is the average, or mean.
Given a set of scores, you are instructed to subtract four points from each score, square the resulting value, and find the sum of the squared numbers. How would this set of instructions be expressed in summation notation?
Σ(x-4)²
In an analysis of variance, if the within-groups variance estimate is about the same as the between- groups variance estimate, then
any difference between sample means is probably due to random sampling error
A researcher measures mean health scores of children at a local school and compares these scores to the mean health score known in the general population. Assuming that the population variance is unknown, what type of t test is appropriate for this?
two-independent-sample t test
