3) According to nerdwallet

3) According to nerdwallet.com, the average household mortgage debt was $ 156,333 in August 2015. Suppose that the current distribution of mortgage debts of all U.S. households has a mean of $ 156,333 and a standard deviation of $ 36,000. Find the probability that the current average mortgage debt of a random sample of 144 U.S. households is a. less than $ 152,400 b. more than $ 160,000 c. $ 152,000 to $ 160,000

4- A house cleaning service claims that it can clean a four-bedroom house in average 2 hours. You want to test the house cleaning service's claim. A sample of n = 81 houses is taken and the sample mean is found to be 1.95 hours and the sample standard deviation is found to be 0.2 hours. Using a 5% level of significance, can you conclude that the house cleaning service'claim is false, corresponding population mean is different from 2 hours?