13. If you take a sample of 5,000 high school graduates and find their average income is $35,000 with a standard deviation of $10,000, and you also take a sample of 6,000 college graduates and find their average income is $50,000 with a standard deviation of $12,500, perform a hypothesis test at 99% confidence to see if there is a statistically significant difference between high school and college graduates' average incomes