Question: 37
(Choose 1 answer)
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a
standard deviation of 40 hours. How large a sample is needed if we wish to be 96% confident that our sample mean will be
within 10 hours of the true mean?
A. 65
B. 47
C. 68
D. 49
E. None of the other choices is correct
Let
20.04 = 1.75, 2002 = 2.05.
