d. What is the probability that the sample average would be between 93 and 96 pounds? 7.19 Suppose a subdivision on the southwest side of Denver, Colorado, contains 1,500 houses. The subdivision was built in 1983. A sample of 100 houses is selected randomly and evaluated by an appraiser. If the mean appraised value of a house in this subdivision for all houses is $177,000, with a standard deviation of $8,500, what is the probability that the sample average is greater than $185,000? 7.20 Suppose the average checkout tab at a large supermarket is $65.12, with a standard deviation of $21.45. Twenty-three percent of the time when a random sample of 45 customer tabs is examined, the sample average should exceed what value? 7.21 According to Nielsen Media Research, the average number of hours of TV viewing per household per week in the United States is 50.4 hours. Suppose the standard deviation is 11.8 hours and a random sample of 42 U.S. households is taken. a. What is the probability that the sample average is more than 52 hours? b. What is the probability that the sample average is less than 47.5 hours