Question 886214
According to R.L. Polk & Co., the average age of cars and light trucks in the U.S. in 2011 was 10.8 years. Assume the standard deviation for this population is 3.7 years. A sample of 35 randomly selected vehicles was selected. What is the probability that the sample mean will be greater than 10 years?
z(10) = (10-10.8)/(3.7/sqrt(35)) = -0.0365
P(x-bar > 10) = P(z > -0.0365) = normalcdf(-0.0365,100) = 0.5146
------------
Cheers,
Stan H.
=========================
 A. 0.5469
 B. 0.7812
 C. 0.8997
 D. 0.9846