Stats final

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

Which measure of effect size is most commonly reported with a t-test

Cohen's d

A researcher must know the population variance in order to compute a t-test

False

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

False

A two-independent sample t-test is used when the same participants are observed two times

False

A researcher conducts a study comparing the obesity rate in a small community to the known obesity rate in the United States. Assuming about the population variance in unknown what type of t-test is appropriate for the study?

One-sample t test

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)?

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. What do you know about the degrees of freedom for each test?

Test 2 is associated with larger degrees of freedom

For an analysis of variance the term of "one way" refers to

The number of factors in the design

MSbn is composed of. And MSwn Is composed of

Treatment variance+ error variance; error variance

A t distribution with infinite degrees of freedom is an z distribution

True

Which of the following is an advantage for selecting related samples compared to selecting independent samples in behavioral research?

all of the above

ANOVA stands for

analysis of variance

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

matched-samples design

The term "between-subjects" refers to

observing different participants one time in each group

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

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

repeated-measures design

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

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

The source of variability associated with error variance in the one way between subjects ANOVA is called

within-groups variability