Exam 3 Practice Questions

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? a. 30 b. 31 c. 32 d. there is not enough information to answer this question

31

a method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called... a. guessing b. hypothesis testing c. random sampling d. level of significance

hypothesis testing

each of the following is an advantage for using the related samples design, except... a. it increases the variability measured in a study b. it can be more practical c. it minimizes standard error d. it increases the power of a research design

it increases the variability measured in a study

based on the effect size conventions, d=0.60 is a... a. large effect size b. small effect size c. medium effect size

medium effect size

computing a one-sample t test is appropriate when... a. the population variance is unknown b. participants are observed one time c. participants are assigned to only one group d. all of the above

all of the above

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... a. mixed measures design b. repeated measures design c. independent samples design d. matched pairs design

repeated measures design

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 significance level? a. satisfaction ratings significantly differ, t(15)=3.60 b. satisfaction ratings significantly differ, t(14)=3.60 c. satisfaction ratings do not significantly differ, t(14)=0.90 d. satisfaction ratings do not significantly differ, t(15)=0.90

satisfaction ratings significantly differ, t(15)=3.60

homogeneity of variance is an assumption for the one-way between subjects ANOVA. what does this assumption mean? a. that one observation has no effect on the likelihood of another observation b. that the variance is equal in each population from which samples are selected c. that the population being sampled from is normally distributed d. that the participants are randomly selected to participate in a sample

that the variance is equal in each population from which samples are selected

using APA format, which value is typically given in parenthesis when reporting the results for a t test? a. the estimate for standard error b. the level of significance c. the degrees of freedom d. the value of the test statistic

the degrees of freedom

what is the definition of "power" in statistics usage? a. the likelihood of retaining a true null hypothesis b. the likelihood of rejecting a true null hypothesis c. the likelihood of retaining a false null hypothesis d. the likelihood of rejecting a false null hypothesis

the likelihood of rejecting a false null hypothesis

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? a. the pooled population variance b. the sample mean for both samples c. the pooled sample variance d. the sample size for both samples

the pooled population variance

for the related samples t test, assuming that all other values remain constant, then as sample size increases... a. the power to detect an effect increases b. the estimate for standard error decreases c. the value of the test statistic increases d. all of the above

all of the above

the t distribution is similar to the z distribution except... a. it is associated with scores being more likely in the tails of the distribution b. it is characterized with greater variability c. it is characterized by "thicker" tails compared to the z distribution d. all of the above

all of the above

which of the following is an assumption for computing any type of independent sample t test? a. data were obtained from a sample that was selected using a random sampling procedure b. the probabilities of each measured outcome in a study are independent c. data in the population being sampled are normally distributed d. all of the above

all of the above

the one-sample z test is a hypothesis test used to test hypotheses... a. concerning at least one population b. concerning the variance in a population c. concerning a single population with a known variance d. all of the above

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. a. critical values b. effect size c. test statistic d. p value

critical values

is a one-sample z test reported differently for one-tailed and two-tailed tests? a. it can be reported differently when the effect size is large b. no, the same values are reported c. it depends on whether the results were significant d. yes, only significant results for a two-tailed test are reported

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 liability ratings, then do likability ratings differ at a .05 level of significance? a. no, this result is not significant, t(30)=1.00 b. yes, this result is significant, p<.05 c. no, this result is not significant, t(30)=0 d. there is not enough information to answer this question, because the variance in each sample is not given

no, this result is not significant, t(30)=0

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? a. it depends on the value of the t statistic b. eta-squared c. omega-squared d. it depends on the sample size

omega-squared

a type of related samples design in which participants are observed more than once is called a... a. repeated measures design b. matched pairs design c. matched samples design d. both B and C

repeated measures design

the estimated standard error in the t statistic uses the ___ to estimate the ___ when the population variance is unknown. a. population variance; sample variance b. degrees of freedom; sample size c. sample variance; population variance d. standard error; sample variance

sample variance; population variance

hypothesis testing is also called... a. random testing b. effect size c. significance testing d. type III error

significance testing

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? a. test 2 is associated with smaller critical values b. each test is associated with the same critical values c. test 1 is associated with smaller critical values d. it depends; there is not enough information to answer this question

test 2 is associated with smaller critical values

state the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20) a. +/- 2.086 b. +/- 0.687 c. +/- 2.093 d. +/- 1.725

+/- 2.086

a researcher selects a sample of 36 dog owners and measures their responsiveness to two types of pictures: one depicting humane treatment of dogs and one depicting 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. a. 0.25 b. 0.21 c. 0.23 d. there is not enough information to answer this question

0.23

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? a. 40 b. 12 c. 39 d. 37

40

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? a. d=0.53 b. d=1.00 c. d=0.34 d. d=0.83

d=0.53

computing a one-way between subjects ANOVA is appropriate when... a. the levels of one or more factors are manipulated b. different participants are observed one time in each of two or more groups for one factor c. the same participants are observed in each of two or more groups for one factor d. all of the above

different participants are observed one time in each of two or more groups for one factor

which of the following is not one of the four steps to hypothesis testing? a. evaluate the plan b. compute the test statistic c. state the hypotheses d. set the criteria for a decision

evaluate the plan

post hoc tests are computed... a. to determine if group means differ, even for tests in which the decision is to retain the null hypothesis b. following a significant ANOVA test to make pairwise comparisons c. prior to conducting a hypothesis test d. to determine which set of degrees of freedom can be attributed to the variability between-groups

following a significant ANOVA test to make pairwise comparisons

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? a. mean scores were significant by 0.88 points in the population b. the effect observed in the population was significant c. mean scores shifted 0.88 standard deviations in the population d. mean scores were significant by 0.88 points in the sample

mean scores shifted 0.88 standard deviations in the population

compared to the two-independent sample t test, the related sample design decreases... a. effect size b. significance c. power d. standard error

standard error

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 hypothesis. a. degrees of freedom b. t distribution c. t statistic d. standard error

t statistic

which of the following summarizes a t test that was significant and associated with a large effect size? a. t(12)=2.95, p<.05, d=.82 b. t(22)=3.02, p<.05, d=.36 c. t(30)=1.03, p>.05, d=.20 d. t(60)=1.76, p>.05, d=.45

t(12)=2.95, p<.05, d=.82

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? a. it depends on whether the test is one-tailed or two-tailed b. to reject the null hypothesis c. to retain the null hypothesis d. there is not enough information to make a decision

to retain the null hypothesis

which design allows you to test an interaction effect? a. two-way ANOVA b. independent groups t test c. one-way ANOVA d. all of the above

two-way ANOVA

a researcher compares differences in positivity between participants in a low, middle, or upper-class family. if she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA? a. (3, 12) b. (2, 42) c. (2, 12) d. (3, 43)

(2, 42)

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. a. 4.35 b. 0.92 c. -4.35 d. -0.92

-4.35

the probability of committing a Type I error is stated by ___; the probability for committing a Type II error is stated by ___. a. the power, the power b. beta, alpha c. alpha, beta d. a p value, a p value

alpha, beta

which measure of effect size is most commonly reported with a t test? a. omega-squared b. cohen's d c. eta-squared d. t statistic

cohen's d

the test statistic for a related samples t test makes tests concerning a single sample of... a. participants scores b. raw scores c. original data d. difference scores

difference scores

____ allows researchers to describe (1) how far mean scores have shifted in the population, or (2) the percentages of variance can be explained by a given variable. a. power b. significance c. effect size d. probability

effect size

which of the following is an assumption for the two-independent sample t test, but not the one-sample t test? a. random sampling b. equal variances c. normality d. independence

equal variances

one difference between a repeated measures design and a matched samples design is... a. only one design involves observing the same participants in each group b. only one design eliminates between-persons variability c. only one design increases the power to observe an effect d. only one design is a type f related sample design

only one design involves observing the same participants in each group

which of the following statements regarding the null hypothesis is true? a. a decision in hypothesis testing is made about the alternative hypothesis, not the null hypothesis b. the null hypothesis is the only hypothesis stated in hypothesis testing c. the null hypothesis always makes statements about a population parameter d. all of the above

the null hypothesis always makes statements about a population parameter

for an analysis of variance, the term "one-way" refers to... a. the number of statistical tests in the design b. the direction that traffic should follow on a road c. the number of factors in the design d. the number of ways that the data can be analyzed

the number of factors in the design

what is the typical level of significance for a hypothesis test in behavioral research? a. .001 b. .50 c. .10 d. .05

.05