Question: In a study of the effects of stress on illness, a researcher tallied the number of colds people contracted during a six 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 condition and the number of subjects precondition are also noted.

Source                          df                      SS                    MS                      F

Between groups                              22.167  

Within groups                                 14.750

Total                                            36.917

Stress Level              Mean                    N

Minimal                     3                     4

Moderate                  4                     4

High                         6                     4

a. Complete the ANOVA Summary Table

b. Is F_obt significant at α'= .05; at α' = .01

c. Perform post hoc comparison if necessary

d. What conclusions can be drawn from the F-ration and the post hoc comparisons

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

f. Graph the means