The Lifetime (In Hours)of a 60-Watt Light Bulb Is a Random

Multiple Choice

The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with  = 30 hours.A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038.What is the 92% confidence interval estimate for the mean lifetime ?

A) (1022.1,1053.9) .
B) (1027.5,1048.5) .
C) (1026.2,1049.8) .
D) (1028.1,1047.9) .
E) (1022.5,1053.5) .