Exam 3 Stats for Psych
A two-independent-sample t test is computed when mean differences are compared between two or more groups sampled from a population with an unknown variance. A. False B. True
A. False
A two-independent-sample t test is used when the same participants are observed two times A. False B. True
A. False
A researcher conducts a study comparing the obesity rate in a small community to the known obesity rate in United States. Assuming that the population variance in unknown, what type of t test is appropriate for this study? A. One sample t-test B. Two- independent sample t test C. Not enough information
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-measure design B. matched- samples design C. Both a and b
A. Repeated-measure design
A t distribution with infinite degrees of freedom is a z distribution A. True B. False
A. True
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. false B. true
A. false
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 in a road
A. the number of factors in the design
A researcher asks a sample of brothers and sisters to rate how positive their family environment was during childhood. In the study, the differences in ratings between each brother and sister pair were compared. The type pf design described here is called ________________. A. Repeated-measures design B. matched-samples design C. both A and B
B. Matched-samples design
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
A researcher tests how well participants know their spouse well under hypnosis, and again without Hipnosis. It was hypothesize that participant response 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 conducts two t tests. Test 1 is a two-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a two-tailed test with a larger sample size at a .05 level of significance. What do you know about the degrees of freedom for each test? A. Test 1 is associated with larger degrees of freedom B. Test 2 associated with with larger degrees of freedom C. Each test score is associated with the same degrees of freedom D. It depends; there is not enough information to answer this question
B. Test 2 is associated with larger degrees of freedom
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. 32 B. 30 C. 31 D. There is not enough information to answer this question
C. 31
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
AVOVA stands for _____________ A. analysis of variety B. Analysis of variable attributes C. analysis of variance D. association of novel operating variable analyses
C. Analysis of variance
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 (1.76)= 1.76, p>.05, d=.45 D. t (12)= 2.95, p<.05, d=.82
D. t(12)= 2.95, p<.05, d=.82
MSbn is composed of ___________, and MSwn is composed of _____________ A. error variance; treatment variance+error variance B. Treatment variance; error variance C. Error variance; treatment variance D. treatment variance + error variance; error variance
D. treatment variance+ error variance; error variance
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
One difference between a repeated-measure design and a matched-sample design is that ______________ A. Only one design is a type 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
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 these
D. All of these
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