Homework Soursea Complete the degrees of freedom for each entry in the ANOV
a) Complete the degrees of freedom for each entry in the ANOVA table.
| A doctor is interested in whether the effectiveness of a new advertising program that encourages more exercise is impacted by gender (i.e., male versus female) or socioeconomic status (SES), which has been categorized into low, medium, and high groups. After the advertising has been in place for a year, the doctor asks study participants about the average amount of weekly exercise they have engaged in for the past three months. She uses a fully-crossed design so that she randomly surveys 21 subjects from each of the gender-SES conditions. | ||||||||||||
| a) Complete the degrees of freedom for each entry in the ANOVA table.
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Solution
SES has been categorised into low, medium and high i.e. 3 groups
So df for SES = 3-1 =2
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There are 2 genders males and females.
Hence df for gender = 2-1 =1
Gender*SES interaction total number = 3x2 =6
Hence df for Gender*SES interaction = 6-1 =5
Total df = 21-1 =20
Error df = 20-(df of gender, ses and gender*ses)
= 20-(1+2+5) = 12
