1. Find the critical valuethat corresponds to the confidence level 88%. Round to 2 decimal places.

2. Use the sample data and confidence level given below to complete parts (a) to (c).

A research institute poll asked respondents if they felt vulnerable to identity theft. In the poll, n = 960, andx = 560 who said "yes". Use a 99% confidence level.

a) Find the value of the best point estimate of the population proportion p.

b) Construct the confidence interval. ( ,)

c) Identify the value of the margin of error E.

3.The brand manager for a brand of toothpaste must plan a campaign designed to increased brand recognition. He wants to first determine the percentage of adults who have heard of the brand. How many adults must be survey in order to be 95% confident that his estimate is within eight percentage points of the true population percentage? Assume that a recent survey suggests that about 88% of adults have heard of the brand.