A manager of the credit department for an oil company would like to determine whether the mean monthly balance of credit card holders is equal to $75. An auditor selects a random sample of 100
Accounts and finds that the mean owed is $83.40 with a sample standard deviation of $23.65. If
You were to conduct a test to determine whether the auditor should conclude that there is
Evidence that the mean balance is different from $75, which test would you use?
A) Z-test of a population mean
B) Z-test of a population proportion
C) t-test of population mean
D) t-test of a population proportion

Question

Quizplus · Accepted Answer

The question is about testing the mean monthly balance of credit card holders, which is a continuous variable. The sample size is 100, which is large enough to use the t-test. Therefore, the correct test to use is the t-test of a population mean.

A Manager of the Credit Department for an Oil Company