In order to estimate the average electric usage per month, a sample of 36 houses was selected and the electric usage was determined. Assume a population standard deviation of 330 kilowatt-hours. Find the standard error of the mean.

Step-by-step explanation:

standard error of the mean. is expressed mathematically as;

is the standard deviation

n is the sample size

Given

Required

Standard error of the mean SM

Substitute the given parameters into the formula shown;

Hence the standard error of the mean is 55.

the answer to the expression is 83