Deck 11: Comparing More Than Two Groups

Question 1

To determine the probability of a Type I error when using multiple comparisons, we use the following formula:

A) 1- (1 - .05)^c.
B) 1- (1 - .95)^c.
c 1- (.95 - .05)^c.
d. 1- (1 - .01)^c.

Answer 1

1- (1 - .05)^c.

Question 2

If I used three t tests to make comparisons between three groups on which I had collected data, the probability of a Type I error would be:

A) .05.
B) .01.
C) .14.
D) .22.

Answer 2

.14.

Question 3

If I used four t tests to make comparisons between four groups on which I had collected data, the probability of a Type I error would be:

A) .05.
B) .01.
C) .14.
D) .19.

Answer 3

.19.

Question 4

The Bonferroni adjustment for a study in which I had three groups I wanted to compare would be:

A) .01.
B) .014.
C) .017.
D) .020.

Question 5

The Bonferroni adjustment for a study in which I had four groups I wanted to compare would be:

A) .01.
B) .017.
C) .0125.
D) .0225.

Question 6

If within-groups variance is large, then we have observed:

A) experimenter effects.
B) an effect of the dependent variable.
C) a large amount of error variance.
D) an effect of the independent variable.

Question 7

If between-groups variance is large, then we have likely observed:

A) experimenter effects.
B) an effect of the dependent variable.
C) enough samples.
D) an effect of the independent variable.

Question 8

When the F-ratio is larger than 1.00, it means that:

A) a mistake has been made in the computation.
B) there are large error effects present.
C) the experimental manipulation probably had the predicted effects.
D) the between-groups variation is no larger than would be expected by chance alone and no larger than the within-groups variance.

Question 9

The smaller the within-groups (error) variance, _____.

A) the more difficult it becomes to show the effects of experimental variance
B) the easier it becomes to show the effects of experimental variance
C) the more difficult it becomes to perform the F test
D) the easier it becomes to show a causal effect of the dependent variable on the independent variable

Question 10

The larger the between-groups variance, _____.

A) the more difficult it becomes to show the effects of experimental variance
B) the easier it becomes to show the effects of experimental variance
C) the more difficult it becomes to perform the F test
D) the smaller the final F-ratio

Question 11

The smaller the between-groups variance, _____.

A) the more difficult it becomes to show the effects of experimental variance
B) the easier it becomes to show the effects of experimental variance
C) the more difficult it becomes to perform the F test
D) the easier it becomes to show a causal effect of the independent variable on the dependent variable

Question 12

The null hypothesis for a one-way randomized ANOVA states that:

A) H₀: $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃.
B) H₀: $\mu$ ₁ $\not =$ $\mu$ ₂ $\not =$ $\mu$ ₃.
C) H_a: $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃.
D) H_a: $\mu$ ₁ $\not =$ $\mu$ ₂ $\not =$ $\mu$ ₃.

Question 13

The alternative hypothesis for a one-way randomized ANOVA states that:

A) H₀: $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃.
B) H₀: $\mu$ ₁ $\not =$ $\mu$ ₂ $\not =$ $\mu$ ₃.
C) H_a: $\mu$ ₁ = $\mu$ ₂ = $\mu$ ₃.
D) H_a: at least one $\mu$ differs from the others_.

Question 14

If the null hypothesis for an ANOVA is true, then the F-ratio should be:

A) greater than 5.00.
B) a negative number.
C) greater than 1.00.
D) 1.00 or less.

Question 15

If the null hypothesis for an ANOVA is false, then the F-ratio should be:

A) greater than 5.00.
B) a negative number.
C) greater than 1.00.
D) 1.00 or less.

Question 16

If the alternative hypothesis for an ANOVA is supported, then the F-ratio should be:

A) greater than 5.00.
B) a negative number.
C) greater than 1.00.
D) 1.00 or less.

Question 17

If the alternative hypothesis for an ANOVA is not supported, then the F-ratio should be:

A) greater than 5.00.
B) a negative number.
C) greater than 1.00.
D) 1.00 or less.

Question 18

What is the Bonferroni adjustment? What would the Bonferoni adjustment be for a study with four groups for which a researcher decided to use t tests for comparisons with $\alpha$ = .05?

Question 19

What do between-groups variance and within-groups variance include?