Question

In a large University, the average age of all the students is 24 years with a standard deviation of 9 years. A random sample of 36 students is selected. a) Determine the standard error of the mean. b) What is the probability that the sample mean will be larger than 19.5

Answer 1

-0.5

Explanation:

σM=σ/√N

=9/√36

=9/6

=3/2=1.5

Z=(x-μ)/σ/√N

=(19.5-24)/9/√36

=-4.5/1.5=-3

The probability that the sample mean will be larger than 19.5 = -0.5

P(>19.5)=P(Z>-3)= -0.5