Consider the data in Exercise 7.90. Suppose that we computed for the population proportion who pay for vehicle registration by mail a confidence interval extending from 0.15 to 0.17. What is the confidence level of this interval?

Data From Exercise 7.90

What is the most common method to renew vehicle registration? In checking a random sample of 1,250 motor vehicle renewal registrations in one county, the finance department found that 200 were mailed, 300 were paid in person at the county finance department office, and the remainder was paid online at the county’s Web site. Phone registration renewals were not available.
a. Estimate the population proportion to pay for vehicle registration renewals in person at the county finance department office. Use a 90% confidence level.
b. Estimate the population proportion of online renewals. Use a 95% confidence level.