PAIRED SAMPLES TTEST
This example is based on:
Tiggemann, M. & Lynch, J. E. (2001). Body image across the life
span in adult women: The role of selfobjectification. Developmental
Psychology, 37(2), 243253.
Body dissatisfaction was measured in adult women (n = 322) ranging
in age from 20 to 84. Using the Figure Rating Scale, the women were
asked to select their current figure and their ideal figure from a series
of silhouette drawings. The drawings were numbered from 1090. Body
dissatisfaction is the discrepancy between the ideal and current ratings.
The following table lists the means that were compared in the study.
Age Group (in years) 
Current Figure 
Ideal Figure 



Entire Sample (n=322) 


M 
46.50 
36.55 
SD 
11.44 
6.38 



2029 (n=75) 


M 
44.75 
34.65 
SD 
12.56 
6.57 



3039 (n=50) 


M 
44.50 
35.54 
SD 
10.98 
5.78 



4049 (n=81) 


M 
45.84 
35.95 
SD 
10.37 
5.32 



5059 (n=43) 


M 
47.79 
38.05 
SD 
10.65 
6.63 



6069 (n=41) 


M 
47.93 
38.00 
SD 
11.72 
6.77 



7085 (n=32) 


M 
51.81 
40.50 
SD 
11.34 
6.48 



Using the data presented in Tiggemann & Lynch's study, we will
perform a power analysis.
