You intend to estimate a population mean $\displaystyle \mu$ from the following sample.

44.5
47.6
27.4
36.4
37
20.5
31
41
47.3
43.8
42.5

Find the 90% confidence interval. You know that the population standard deviation is 14

< $\displaystyle \mu$ <

Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to the 4th digit.