Quiz 8 (Chapters 13-14)

Which of the following is not used in an F-ratio for the two-factor analysis of variance? MS(B) MS(within-treatments) MS(A) MS(between-treatments)

MS(between-treatments)

What is the correct denominator for the repeated-measures F-ratio? MS(between-treatments) MS(between-subjects) MS(within-treatments) MS(error)

MS(error)

When using the Scheffe post hoc test for a repeated-measures ANOVA, the denominator for the F-ratio in the Scheffe test should be ________. MS(error) MS(within-treatments) MS(between-subjects) MS(between-treatments)

Ms(error)

In a repeated-measures analysis of variance (RMANOVA), how does the magnitude of the mean differences from one treatment to another contribute to the F-ratio? The mean differences add to the numerator of the F-ratio. The mean differences add to both the numerator and the denominator of the F-ratio. The sample mean differences do not influence the F-ratio. The mean differences add to the denominator of the F-ratio.

The mean differences add to the numerator of the F-ratio.

Two variables are said to interact when _____________. both variables produce a change in the subjects' scores. the effect of one independent variable depends on the levels of the second variable. both variables are equally influenced by a third factor. the two variables are differentially affected by a third variable.

the effect of one independent variable depends on the levels of the second variable.

In a two-factor analysis of variance, a main effect is defined as _________. the difference between the largest treatment mean and the smallest treatment mean. the mean difference between the two factors. the mean differences among the levels of one factor. the mean differences among all treatment conditions.

the mean differences among the levels of one factor.

Which of the following is used to calculate the degrees of freedom for the AxB interaction in a two-way ANOVA? df(between-treatments) - df(A) - df(B) df(between-treatments) - df(within-treatments) df(A) - df(B) df(within-treatments) - (df(A) + df(B))

df(between-treatments) - df(A) - df(B)

In analysis of variance, each independent variable is referred to as a ___________. stage. level. factor. comparison.

factor

The results of a repeated-measures ANOVA are reported as follows: F(3,27) = 1.12, p > 0.05. How many treatment groups were compared in the study? 27 4 28 3

4

For a research study with two levels of factor A, three levels of factor B, and n=5 in each treatment condition, what are the df values for the F-ratio evaluating the main effects for factor A? 1, 24 1, 4 1, 29 2, 29

1, 24 (Specifically, MS(A) = k-1 for factor A = 2 levels - 1 = 1. The MS(within-treatments) for the study is the sum of the df's for each of the six treatment groups of n=5 -- hence, 6 * (5-1) = 24.)

How many separate groups of participants would be needed for an independent-measures, two-factor study with 3 levels of factor A and 4 levels of factor B? 12 7 3 4

12 (3 levels x 4 levels = 12 treatment groups. )

For a repeated-measures study comparing three treatment conditions with a sample of n=10 participants, what are the degrees of freedom for the repeated-measures F ratio? 2, 18 2, 9 3, 18 3, 9

2, 18 (Specifically, the df(between-treatments) = k-1 = 3-1 = 2, and the df(error) = df(within-treatments) - df(between-SUBJECTS) = (9+9+9) - (10-1) = 27 - 9 = 18.)

For a repeated-measures study comparing three treatment conditions with a sample of n=4 participants, what are the degrees of freedom for the repeated-measures F ratio? 2, 11 2, 9 2, 6 3, 11

2, 6 (Specifically, the df(between-treatments) = k-1 = 3-1 = 2, and the df(error) = df(within-treatments) - df(between-SUBJECTS) = (3+3+3) - (4-1) = 9 - 3 = 6. )

A researcher reports an F-ratio with df = 2, 40 from a repeated-measures ANOVA. How many subjects participated in this experiment? 63 41 44 21

21 (we know from df(bt) = 2 that there were three treatment groups, so k = 3. We know that df(error) = (k-1)(n-1) as a rule. So, 40 = (3-1)(n-1), 40 = 2n-2, 42 = 2n, n = 21.)

A repeated-measures study uses a sample of n=15 participants to evaluate the mean differences among four treatment conditions. In the analysis of variance for this study, what is the value for df(between-treatments)? 14 59 4 3

3

A repeated-measures analysis of variance produces SS(total) = 40 and SS(within-treatments) = 10. For this analysis, what is SS(between-treatments)? 30 400 Cannot be determined without additional information. 50

30

For a two-factor study with 2 levels of factor A, 2 levels of factor B, and a separate sample of n=10 participants in each treatment condition, what is df(within-treatments)? 9 18 39 36

36 (Specifically, we know there are 2x2 = 4 treatment groups, x10 participants per group = 40 participants total. The value of df(within-treatments) is the sum of the df of each individual treatment group, so (10-1) * 4 = 9*4 = 36.)

A repeated-measures ANOVA produces SS(between-treatments) = 30 and MS(between-treatments) = 10. In this analysis, how many treatment conditions are being compared? 4 5 3 20

4 (SS(bt)/MS(bt) = df(bt) = 30/10 = 3, and the number of treatment conditions = df(bt)+1.)

For a repeated-measures study comparing three treatment conditions with a sample of n=4 participants, the participant totals (values of "P") are 3, 6, 9, and 6, and the SS values within each of the treatment groups are SS1 = 2, SS2 = 2, and SS3 = 6. What is the value of SS(error)? 6 10 4 2

4 (Specifically, SS(within-treatments) = 2+2+6 = 10. SS(between-SUBJECTS) = (sigma P^2)/k - (G^2/n) = 9/3 + 36/3 + 81/3 + 36/3 - 24^2/12 = 6. SS(error) = SS(within-treatments) - SS(between-SUBJECTS) = 10 - 6 = 4.)

For an experiment involving 3 levels of factor A and 3 levels of factor B, with a sample of n=8 in each treatment condition, what are the df values for the F-ratio for the AxB interaction? 6, 63 4, 63 2, 63 8, 63

4, 63 (Specifically, there are 9 treatment groups (3 levels of A x 3 levels of B), with n=8 each, so a total of 72 participants. df(within) = the sum of the df of each treatment group, so 9 x (8-1) = 63. df(between-treatments) = 9-1 = 8. df(A) = 3-1 = 2. df(B) = 3-1 = 2. df(AxB) = 8 - 2 - 2 = 4. Hence, the df(AxB) = 4, 63. )

A repeated-measures ANOVA with n=5 subjects has df(within-treatment) = 12. What is the value for df(error) for this analysis? 48 16 Cannot determine df(error) without additional information. 8

8 ( df(error) = df(within-treatment) - df(between-SUBJECTS) = 12 - (5-1) = 8.)

A two-factor research study is used to evaluate the effectiveness of a new blood-pressure medication. In this two-factor study, Factor A is medication versus no medication (2 levels) and Factor B is male versus female (2 levels). The medicine is expected to reduce blood pressure for both males and females, but is expected to have a much greater effect on males. What pattern of results should be obtained if the medication works as predicted? A significant main effect for factor A (medication) and a significant interaction. A significant interaction between factors A and B. A significant effect for factor A (medication). None of the other answers is correct.

A significant main effect for factor A (medication) and a significant interaction. (If the drug affects all sexes to some extent, that is evidence for a main effect of drug. If the drug affects one sex more than the other, that is evidence for an interaction between drug and sex. )

In a two-factor ANOVA, what is the implication of a significant AxB interaction for the main effects? Neither of the two main effects can be significant. The significance of the interaction implies nothing about the significance of the main effects. At least one of the main effects also must be significant. Both of the main effects also must be significant.

The significance of the interaction implies nothing about the significance of the main effects.

In an independent-measures ANOVA, individual differences contribute to the variance in the numerator and in the denominator of the F-ratio. For a repeated-measures ANOVA, what happens to the individual differences in the numerator of the F-ratio? None of the other options accurately describes individual differences in the numerator. Individual differences contribute to the variance in the numerator. They do not exist because the same individuals participate in all of the treatments. They are measured and subtracted out in the second stage of the analysis.

They do not exist because the same individuals participate in all of the treatments.

What is the relationship among the three separate F-ratios in a two-factor ANOVA? They all have the same df values, but may have different denominators. They may have different df values, but they all have the same denominator. They may have different df values, and may have different denominators. They all have the same df values, and they all have the same denominator.

They may have different df values, but they all have the same denominator.