7.55. From Example 6.4 (page 151) in Chapter 6, for the cognitive behavioral therapy group the sample mean change in weight of 3.0 pounds was significantly different from 0. However, Example 7.7

(page 198) showed it is not significantly different from the mean change for the control group, even though that group had a negative sample mean change. How do you explain this paradox? {Hint:

From Sections 7.1 and 7.3, how does the se value for estimating a difference between two means 7.56. A survey by the Harris Poll of 2201 Americans in 2003 indicated that 51 % believe in ghosts and 31 %

believe in astrology.

(a) Is it valid to compare the proportions using inferential methods for independent samples?

Explain.

(b) Do you have enough information to compare them using inferential methods for dependent samples? Explain.