Question

The mean age for all Foothill College students for a recent Fall term was 33.2. The population standard deviation has been pretty consistent at 15. Suppose that thirty-six Winter students were randomly selected. The mean age for the sample was 30.4. We are interested in the true mean age for Winter Foothill College students. Let X = the age of a Winter Foothill College student. Construct a 90% Confidence Interval for the true mean age of Winter Foothill College students by working out then answering the exercise. Identify the upper limit.

Answer 1

Given:

=30.4 , = 15 , n= 36

90% confidence interval for is

Z * /

The value of Z at 0.10 alha level is 1.64

90% CI is

30.4 1.64 * 15/

( 26.3 , 34.5)

# The upper limit is 34.5