Psych 311 exam #3 terms

As_____________________________ increases, the power to detect an effect increases.

sample size

Rejecting a true null hypothesis is a Type____________________error.

1

For an analysis of variance, the term "one-way" refers to A) the number of factors in the design B) the number of statistical tests in the design C) the number of ways that the data can be analyzed D) the direction that traffic should follow on a road

A) the number of factors in the design

A researcher reports a significant effect with t(14) = 3.24. Compute eta-squared for this result. A) = 0.43 (large effect size) B) = 0.43 (medium effect size) C) = 0.37 (large effect size) D) = 0.37 (medium effect size)

A) = 0.43 (large effect size

Is a one-sample t test reported differently for one-tailed and two-tailed tests? A) No, the same values are reported. B) It depends on whether the results were significant. C) Yes, only significant results for a two-tailed test are reported. D) It can be reported differently when the effect size is large.

A) No, the same values are reported.

A researcher assigns 21 adolescents to rate the likability of a person described in a vignette as having one of three personality traits. An equal number of participants are assigned to each group. If = 4.08 for this study, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? A) Reject the null hypothesis. B) Retain the null hypothesis. C) There is not enough information to answer this question

A) Reject the null hypothesis.

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? A) Researcher A. B) Researcher B. C) The likelihood is the same for both researchers. D) There is not enough information to answer this question.

A) Researcher A

Two researchers (A and B) compute a two-independent sample t test. For both tests, the mean difference between the two groups is 10, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis? A) Researcher A. B) Researcher B. C) The likelihood is the same for both researchers. D) There is not enough information to answer this question.

A) Researcher A.

A researcher conducts two studies. Each study was a one-sample z test. Both studies placed the rejection region in both tails and measured the same sample mean. The alpha level in Study 1 was larger than the alpha level used in Study 2. Which study is associated with greater power to detect an effect? A) Study 1 B) Study 2 C) They are associated with the same level of power.

A) Study 1

The mean crying time of infants during naptime at a local preschool is 12 minutes. 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. Test whether this new naptime routine reduced crying time at a .05 level of significance. A) The new naptime routine significantly reduced crying time, t(24) = -4.35, p < .05. B) The new naptime routine did not reduce crying time, t(24) = -4.35, p < .05. C) The new naptime routine did not reduce crying time, t(24) = 0.92, p > .05. D) The new naptime routine significantly reduce crying time, t(24) = 0.92, p < .05.

A) The new naptime routine significantly reduced crying time, t(24) = -4.35, p < .05.

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 stated in hypothesis testing. D) all of the above

A) The null hypothesis always makes statements about a population parameter.

A researcher computes a test statistic and finds that the p value for this test is .03. What does this result mean? A) There is a 3% likelihood of obtaining the test statistic value, if the null were true. B) The probability of committing a Type I error if we retain the null hypothesis is 3%. C) The probability of committing a Type II error if we reject the null hypothesis is 3%. D) There is a 3% likelihood that the researcher's hypothesis is correct.

A) There is a 3% likelihood of obtaining the test statistic value, if the null were true.

The one-sample z test is a hypothesis test used to test hypotheses A) concerning a single population with a known variance B) concerning at least one population C) concerning the variance in a population D) all of the above

A) concerning a single population with a known variance

A researcher 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; medium effect size B) d = 0.53; large effect size C) d = 0.34; small effect size D) d = 0.34; medium effect size

A) d = 0.53; medium effect size

Computing a one-way between-subjects ANOVA is appropriate when A) different participants are observed one time in each of two or more groups for one factor B) the same participants are observed in each of two or more groups for one factor C) the levels of one or more factors are manipulated D) all of the above

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

Which measure of proportion of variance tends to OVERESTIMATE the size of an effect in a population? A) eta-squared B) omega-squared C) none of the above

A) eta-squared

Which of the following is NOT a post hoc test for a one-way between-subjects ANOVA? A) eta-squared B) Fisher's LSD test C) Tukey's HSD test D) Bonferroni test

A) eta-squared

The criteria for a decision regarding the value stated in a null hypothesis is set by the A) level of significance B) p value C) probability value D) both A and B

A) level of significance

You read about a study testing whether night shift workers sleep the recommended 8 hours per day. Assuming that the population variance of sleep (per day) is unknown, what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C) There is not enough information to answer this question.

A) one-sample t test

A researcher compares the difference in the amount of texting by students in class during the first week and last week of classes. The type of design described here is called a A) repeated measures design B) matched samples design C) both A and B

A) repeated measures design

The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown. A) sample variance; population variance B) population variance; sample variance C) standard error; sample variance D) degrees of freedom; sample size

A) sample variance; population variance

A researcher conducts a study using the one-way between-subjects ANOVA. He computes = 120 and = 200. What is the effect size for this test using eta-squared? A) 0.60 B) 0.38 C) 1.67 D) There is not enough information to answer this question.

B) 0.38

The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many pairwise comparisons need to be made for this ANOVA result? A) 2 B) 3 C) 4 D) 12

B) 3

When the variability attributed to between-groups is equal to the variability attributed to error, then the value of the test statistic for a one-way between-subjects ANOVA is, A) Equal to 0. B) Equal to 1. C) Significant at any sample size. D) Undefined in that the test statistic cannot be computed in this case.

B) Equal to 1.

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 ratings in each group were 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? A) Yes, this result is significant, p < .05. B) No, this result is not significant, t(30) = 0. C) No, this result is not significant, t(30) = 1.00. D) There is not enough information to answer this question, because the variance in each sample is not given.

B) No, this result is not significant, t(30) = 0.

A researcher randomly assigned 32 children to observe a short clip depicting either their favorite superhero, a parent, a teacher, or no person at all (n = 8 per group). If = 30 and = 104, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? A) Reject the null hypothesis. B) Retain the null hypothesis. C) There is not enough information to answer this question.

B) Retain the null hypothesis.

A researcher tests how well participants know their spouse while under hypnosis, and again without hypnosis. It was hypothesized that participant responses would be more accurate (greater number of correct responses) when under hypnosis. The mean number of correct responses was M = 5.30 under hypnosis and M = 3.40 without hypnosis in a sample of 30 participants. If the estimated standard error for difference scores was 2.52, then what is the decision at a .05 level of significance (two-tailed test)? A) Retain the null hypothesis; responses were more accurate under hypnosis. B) Retain the null hypothesis; responses were not more accurate under hypnosis. C) Reject the null hypothesis; responses were more accurate under hypnosis. D) Reject the null hypothesis; responses were not more accurate under hypnosis.

B) Retain the null hypothesis; responses were not more accurate under hypnosis.

A researcher measures deviant behavior in a sample of 12 children from abusive homes (Sample A). Another researcher measures the same behavior in a sample of 18 children from abusive homes (Sample B). Which sample is associated with larger degrees of freedom? A) Sample A B) Sample B C) Each sample has the same degrees of freedom. D) There is not enough information to answer this question.

B) Sample B

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 1 is associated with smaller critical values. B) Test 2 is associated with smaller critical values. C) Each test is associated with the same critical values. D) It depends; there is not enough information to answer this question.

B) Test 2 is associated with smaller critical values.

All other things being equal, as the sample size increases, what happens to the critical value for a related samples t test (or for any t test, for that matter)? A) The critical value increases. B) The critical value decreases. C) The critical value does not change. D) It depends on the value of the test statistic.

B) The critical value decreases.

Which of the following post hoc tests is associated with the LEAST power to detect an effect? A) Fisher's LSD test B) Tukey's HSD test C) Studentized Newman-Keuls D) None; each post hoc test is associated with the same power to detect an effect.

B) Tukey's HSD test

A researcher reports that mean ratings of liking for some food are 0.8±2.4 (M±SD). If the null hypothesis was that the mean equals 0, then what is the effect size for this test using estimated Cohen's d? A) d = 0.33; small effect size B) d = 0.33; medium effect size C) d = 3.00; large effect size D) There is not enough information to answer this question.

B) d = 0.33; medium effect size

The test statistic for a related samples t test makes tests concerning a single sample of A) raw scores B) difference scores C) participant scores D) original data

B) difference scores

A researcher asks a sample of brothers and sisters to rate how positive their family environment was during childhood. In this study, the differences in ratings between each brother and sister pair were compared. The type of design described here is called a A) repeated measures design B) matched samples design C) both A and B

B) matched samples design

Using a between-subjects ANOVA design, A) participants are each observed one time B) n participants are observed k times C) data are not analyzed between groups D) the same participants are observed in each group

B) n participants are observed k times

The term "between-subjects" refers to A) observing the same participants in each group B) observing different participants one time in each group C) the type of post hoc test conducted D) the type of effect size estimate measured

B) observing different participants one time in each group

The power of the decision-making process is A) stated by an alpha level B) the likelihood of rejecting a false null hypothesis C) the same as a null finding D) the likelihood of committing a Type I error

B) 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 sample variance B) the pooled population variance C) the sample size for both samples D) the sample mean for both samples

B) the pooled population variance

To compute a related samples 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 estimated standard error for difference scores B) the population variance of difference scores C) the sample size or number of pairs of scores D) the sample variance of difference scores

B) the population variance of difference scores

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) to reject the null hypothesis B) to retain the null hypothesis C) It depends on whether the test is one-tailed or two-tailed. D) There is not enough information to make a decision.

B) to retain the null hypothesis

Given the following values: = 6.0, M = 7.6, n = 36, = 6, conduct a one-sample z test at a .05 level of significance. For a one-tailed test, upper-tail critical, what is the decision? A) to reject the null hypothesis B) to retain the null hypothesis C) There is not enough information since the sample size is not given.

B) to retain the null hypothesis

A researcher records differences in ratings of emotion among participants watching either a drama or a romance film. Assuming that the population variance is unknown, what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C)There is not enough information to answer this question.

B) two-independent sample t test

The source of variability associated with error variance in the one-way between-subjects ANOVA is called A) between-groups variability B) within-groups variability C) degrees of freedom D) both A and B

B) within-groups variability

Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean? A) that the population being sampled from is normally distributed B) that participants are randomly selected to participate in a sample C) that the variance is equal in each population from which samples are selected D) that one observation has no effect on the likelihood of another observation

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

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? A) 3.07 B) 3.44 C) 3.47 D) 4.32

C) 3.47

A professor gives an exam in which the mean score is 78 points. She gives another exam to test whether or not scores change. In this example, the null hypothesis is A) ≠ 78 B) M ≠ 78 C) = 78 D) M = 78

C) = 78

Following a significant one-way between-subjects ANOVA in which k > 2, what is the next appropriate step? A) Summarize the data; no further tests are required. B) Interpret the data; no further tests are required. C) Conduct post hoc tests. D) both A and B

C) Conduct post hoc tests.

Post hoc tests are computed A)Prior to conducting a hypothesis test. B) To determine which set of degrees of freedom can be attributed to the variability between-groups. C) Following a significant ANOVA test to make pairwise comparisons. D) to determine if groups means differ, even for tests in which the decision is to retain the null hypothesis.

C) Following a significant ANOVA test to make pairwise comparisons.

Two researchers analyze the same data set. Researcher A uses a two-independent sample t test and decides to retain the null hypothesis. Researcher B uses a related samples t test and decides to reject the null hypothesis. Which of the following is a likely explanation for the disparity in the decisions made. A) The two-independent sample t test had greater power to detect the effect. B) The two-independent sample t test was associated with fewer degrees of freedom. C) The related samples t test had greater power to detect the effect. D) The related samples t test was associated with more degrees of freedom.

C) The related samples t test had greater power to detect the effect.

One difference between a repeated measures design and a matched samples design is that A) only one design is a type of related sample design B) only one design increases the power to observe an effect C) only one design involves observing the same participants in each group D) only one design eliminates between-persons variability

C) only one design involves observing the same participants in each group

A researcher conducts a study in which the population variance of difference scores between two groups is unknown. What type of t test is most appropriate for this study? A) one-sample t test B) two-independent sample t test C) related samples t test D) There is not enough information to answer this question.

C) related samples t test

A researcher conducts a study in which the same participants are observed across each level of the independent variable. If there are only two levels of the independent variable, then what type of t test is appropriate for this study? A) one-sample t test B) two-independent sample t test C) related samples t test D) There is not enough information to answer this question.

C) related samples t test

Compared to the two-independent sample t test, the related samples design decreases A) power B) effect size C) standard error D) significance

C) standard error

In a study with three groups and 13 participants in each group, the sum of squares for the within-groups source of variation is 18. What is the value for the mean square within-groups in this study? A) 2 B) 3 C) 9 D) 0.5

D) 0.5

A researcher measures differences in recall between male and female participants following a romantic movie clip. If different participants were in each group, then what type of statistical design is appropriate for this study? A) a two-independent sample t test B) a one-way between-subjects ANOVA C) a two-way between-subjects ANOVA D) both A and B

D) both A and B

Which of the following is an advantage for selecting related samples compared to selecting independent samples in behavioral research? A) Selecting related samples can be more practical. B) Selecting related samples minimizes standard error. C) Selecting related samples increases power. D) All of the above.

D) All of the above.

Which measure of effect size is most commonly reported with a t test? A) eta-squared B) omega-squared C) t statistic D) Cohen's d

D) Cohen's d

Which of the following is an assumption for the two-independent sample t test, but not the one-sample t test? A) Normality B) Random sampling C) Independence D) Equal variances

D) Equal variances

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) The effect observed in the population was significant. B) Mean scores were significant by 0.88 points in the sample. C) Mean scores were significant by 0.88 points in the population. D) Mean scores shifted 0.88 standard deviations in the population.

D) Mean scores shifted 0.88 standard deviations in the population.

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? A) Satisfaction ratings do not significantly differ, t(14) = 0.90. B) Satisfaction ratings do not significantly differ, t(15) = 0.90. C) Satisfaction ratings significantly differ, t(14) = 3.60. D) Satisfaction ratings significantly differ, t(15) = 3.60.

D) Satisfaction ratings significantly differ, t(15) = 3.60.

Computing a two-independent sample t test is appropriate when A) different participants are assigned to each group B) the population variance is unknown C) participants are observed one time D) all of the above

D) all of the above

For the related samples t test, assuming that all other values remain constant, then as samples size increases A) the value of the test statistic increases B) the power to detect an effect increases C) the estimate for standard error decreases D) all of the above

D) all of the above

Which of the following is an assumption for computing a one-way between-subjects ANOVA? A) The population being sampled from is normally distributed. B) Participants were selected to participate using a random procedure. C) One observation has no effect on the likelihood of another observation. D) all of the above

D) all of the above

When reporting the results of a one-sample z test using APA format, the ________ does not need to be reported. A) Test statistic B) p value C) effect size D) critical values

D) critical values

Each of the following is an advantage for using the related samples design, except A) it can be more practical B) it minimizes standard error C) it increases the power of a research design D) it increases the variability measured in a study

D) it increases the variability measured in a study

The denominator of the test statistic for a related samples t test A) compares mean differences observed to the mean differences stated in a null hypothesis B) is the sum of the difference scores for each participant C) provides an estimate of the error associated with the original scores D) provides an estimate of the error associated with the difference scores

D) provides an estimate of the error associated with the difference scores

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

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

A professor finds that the average SAT score among all students attending his college is 1150±150 (). He polls his class of 25 students and finds that the average SAT score is 1200. Suppose he computes a one-sample z test at a .05 level of significance. What is his decision? A) to reject the null hypothesis B) to retain the null hypothesis C) to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed test D) to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test

D) to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test