Find the Necessary Sample Size

Multiple Choice

Find the necessary sample size.
-The monthly earnings of a group of business students are are normally distributed with a standard deviation of 545 dollars. A researcher wants to estimate the mean monthly earnings of all business
Students. Find the sample size needed to have a confidence level of 95% and a margin of error of
128 dollars.

A) 2
B) 5
C) 61
D) 70