In order to estimate the mean 30-year fixed mortgage rate for a home loan in the United States, a random sample of 15 recent loans is taken.
The average calculated from this sample is 7.85%. It can be assumed that 30-year fixed mortgage rates are normally distributed with a standard deviation of 0.6%. Compute 90% and 95% confidence intervals for the population mean 30-year fixed mortgage rate.
Use Table 1. (Round intermediate calculations to 4 decimal places. Round "z-value" to 3 decimal places and final answers to 2 decimal places. Enter your answers as percentages, not decimals.)
| Confidence Level |
Confidence Interval |
| 90% |
% |
to |
% |
| 95% |
% |
to |
% |