Answer to Question #257496 in Statistics and Probability for Mackie

Question

A certain bank issues its own credit card. The head of credit collection department found out that the mean amount of unpaid balance of the credit card holders was Php 25,000.00 and with a standard deviation of Php 1,500.00. The head of the bank wanted to find out whether the mean amount of unpaid balance was really Php 25,000.00. He sample 40 credit card holders and found out a sample mean of Php 23,900.00. Can the head of the credit collection department conclude that the unpaid balance is less than Php 25,000.00? Use the 0.01 alpha level. Illustrate the data using a Normal Distribution Curve. Refer the critical value from the Z-Scores Distribution Table or Standard Normal Probabilities Table.