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

Selecting related samples can be more practical, Selecting related samples minimizes standard error, Selecting related samples increases power.

MSbn is composed of ______, and MSwn is composed of ______.

Treatment variance + error variance; error variance

ANOVA stands for

analysis of variance

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

cohen's D

Which of the following summarizes a t test that was significant and associated with a large effect size?

cohen's d

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

false

true or 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

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

false

The term "between-subjects" refers to ______.

observing different participants one time in each group

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

one sample t test

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

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?

test 2 is associated with larger degrees of freedom

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

the number of factors in the design

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

true or false 1. A t distribution with infinite degrees of freedom is a z distribution

true

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

within groups and between group variability

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

matched-samples design

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