1. Warm Up
A Gallup poll asked 1600 adults in the U.S. “Did you attend church in the past 7 days?” 715 people said yes. Assume the survey used a simple random sample. Calculate a 90% confidence interval for the proportion of all adults in the U.S. who attended church in the past 7 days.

2. Practice
1) A recent Gallup poll found that 42% of Americans approve of the job Trump is doing in office. The poll had a 95% confidence level and quoted a margin or error of +/- 3%. If they plan to repeat the survey next month, at least how many Americans do they need to sample to be sure of getting a margin of error of no more than 3%? 2) Another poll taken by CNN also found a that 42% of voters approved of the president. This survey randomly sampled 1800 potential voters and had a margin of error of +/- 2.7%. What is the confidence level that was used for this calculation?