Suppose that in 2017, 52% of U. S. households had only wireless telephone service (no landlines). Suppose that in 2021, 56% of a random sample of 100 U. S. households had only wireless telephone service. 1. Using the proportion from 2017, calculate the standard error. (Remember, in the modules this test covers, we usually use the earlier year's proportion as an estimate of this year's proportion when we are calculating the standard error.)

2. Does the data allow the use of a normal model for our calculations? Explain your reasoning.

3. In this part of the test, we'll go ahead and use a normal model, regardless of whether you got "yes" or "no" as your answer to part (b). Using a normal model, calculate the approximate 95% confidence interval for the percentage of all U. S. households in 2021 that have only wireless telephone service. Explain your reasoning.