A random variable has a normal distribution with a mean of 1

A random variable has a normal distribution with a mean of 117 and a standard deviation of 54. If the sample size is 20, what is the standard deviation of the sample average? State your answer rounded to two decimal places.

Solution

The standard error of the mean is given by

SE = s/sqrt(n)

= 54/sqrt(20)

= 12.07 [ANSWER]