In each part, identify whether it would be more appropriate to use a procedure for paired data or a procedure for two independent samples to estimate the difference of interest.

a. A researcher wants to estimate the difference between the mean scores on a memorization test for people over 60 years old and people under 40 years old.

b. Women give their actual and desired weights in a survey.

An estimate of the mean difference is desired.

c. Two treatments for reducing cholesterol are compared.

Forty people with high cholesterol use the first treatment, and 40 other people with high cholesterol use the second treatment. An estimate of the difference between the mean decrease in cholesterol for Treatment 1 and the mean decrease in cholesterol for Treatment 2 is desired.