# In a study of the effects of stress on illness, a researcher tallied

#1 In a study of the effects of stress on illness, a researcher tallied the number of colds people contracted during a 6-month period as a function of the amount of stress they reported during that same time period. There were three stress levels: minimal, moderate, and high stress. The sums of squares appear in the following ANOVA summary table. The mean for each condition and the number of subjects precondition are also noted.

Stress Level Mean N

Minimal 3 4

Moderate 4 4

High 6 4

1. Complete the ANOVA summary table.

2. Is Fobt significant at α = .05; at α = .017

3. Perform post hoc comparisons if necessary.

1. What conclusions can be drawn from the F –ratioand the post hoc comparison?

1. What is the effect size the effect size, and what does this mean?

1. Graph the means.

#2 A researcher conductedan experiment on the effects of a new “drug” on depression. The researcher had a control group that received nothing, a placebo group, and an experimental group that received the “drug”. A depression inventory that provide a measure of depression on a 50-point scale was used (50 indicates that anindividual is very high on the depression variable). The ANOVA summary table appears next, along with the mean depression score for each condition.

Drug” Condition Mean N

Control 36.26 15

Placebo 33.33 15

“Drug” 24.13 15

1. Complete the ANOVA summary table.

2. Is Fobt significant at α = .05; at α = .017

1. Perform post hoc comparisons if necessary.

1. What conclusions can be drawn from the F – ratioand the post hoc comparison?

2. What is the effect size the effect size, and what does this mean?

3. Graph the means.

#3 A researcher has been hired by a pizzeria to determine which type of crust customers prefer. The restaurant offers three types of crust: hand-tossed, thick, and thin. Following are the mean of number of 1-inch pieces of pizza eaten for each condition from 10 subjects who had the opportunity to eat as many pieces with each type of crust as they desired. The ANOVA summary table also follows.

Crust Type Mean N

Hand-tossed 2.73 10

Thick 4.20 10

Thin 8.50 10

1. Complete the ANOVA summary table.

2. Is Fobt significant at α = .05; at α = .017

1. Perform post hoc comparisons if necessary.

1. What conclusions can be drawn from the F – ratioand the post hoc comparision?

1. What is the effect size the effect size, and what does this mean?

1. Graph the means.