Exhibit 8-4 In Order to Estimate the Average Electric Usage Per Month

Multiple Choice

Exhibit 8-4
In order to estimate the average electric usage per month, a sample of 81 houses was selected, and the electric usage was determined. Assume a population standard deviation of 450-kilowatt hours.
-Refer to Exhibit 8-4. At 95% confidence, the size of the margin of error is

A) 1.96
B) 50
C) 98
D) 42