Satisfying Congress. Exercise 3.12 describes a sample survey of 1004 adults, with margin of error ±3% for 95% confidence.

(a) A member of Congress thinks that 95% confidence is not enough. He wants to be 99% confident. How would the margin of error for 99% confidence based on the same sample compare with the margin of error for 95% confidence?

54 CHAPTER 3 What Do Samples Tell Us?

(b) Another member of Congress is satisfied with 95% confidence, but she wants a smaller margin of error than ±3 percentage points. How can we get a smaller margin of error, still with 95% confidence?

AppendixLO1