The economy may be headed for recession. As the manager of a bank, you would like to know the average income of the bank's credit card customers. A sample of 100 randomly selected customers yields a mean income of $61,015.56 and a standard deviation of $2000.
Q. What is the 90% confidence interval for the mean salary of your credit card customers?
Q. Which of the following conclusions can be made from the previous interval with at least 90% confidence?
I. Less than 10% of the customers of the bank have an income greater than $65,000
II. The average customer in your sample has an income of more than $61,000
III. The probability that the true population mean is between the two values you derived in the previous question is 0.90