Researchers randomly assigned 33 participants suffering from

Researchers randomly assigned 33 participants suffering from generalized anxiety disorder (GAD) to the three levels of a treatment IV (cognitive behavioral, group therapy, and no treatment control) and measured outcome by administering a measure of anxiety that ranged in total score from 1 to 50 with higher scores indicating more anxiety. When the researchers analyzed the data, they obtained the following ANOVA summary table with certain values missing. To answer questions pertaining to these data, you will need to solve for the missing values.

Source

df

SS

MS

F

Treatment

2

?

1100

?

?

2700

?

32

4900

What is the F statistic (carried to two decimal places) in this ANOVA summary table?

Solution

df(err) = 32 - 2 = 30

SS(tre) = 4900 - 2700 = 2200

MS(err) = SS(err)/df(err) = 90

Thus,

F = MS(tre)/MS(err) = 12.22 [ANSWER]