1. We like to determine the current percentage of households using e-mail. How many households must be surveyed to be 90% confident that the sample percentage is within four percentage points? Ten years ago the percentage of US househlds using email was 45%.
2. In a survey of 200 smokers, 175 reported they wanted to quit smoking. Consturct a 99% for the true percentage of US households using email was 45%.