Find the Confidence Interval Specified $\sigma =$ 071 Minutes $\mu$ To Polish a Shoe

Multiple Choice

Find the confidence interval specified.
-A sample of 38 people were randomly selected from among the workers in a shoe factory. The time taken for each person to polish a finished shoe was measured. The sample mean was 4.0 minutes.
Assume that $\sigma =$ 0.71 minutes. Construct a 90% confidence interval for the true mean time, $\mu$ to Polish a shoe.

A) 3.70 to 4.30 minutes
B) 3.81 to 4.19 minutes
C) 3.73 to 4.27 minutes
D) 3.77 to 4.23 minutes