Chapter 12.3, Problem 136E

Eating Out Vegetarian. Refer to the study on ordering vegetarian considered in Examples 12.8-12.10.

1. a. Without making a guess for the observed values of the sample proportions, find the common sample size that will ensure a margin of error of at most 0.01 for a 90% confidence interval. Hint: Use Exercise 12.133.
2. b. Find a 90% confidence interval for p₁-p₂ if, for samples of the size determined in part(a), 38.3% of the men and 43.7% of the women sometimes order veg.
3. c. Determine the margin of error for the estimate in part (b), and compare it to the required margin of error specified in part (a).