0 Question 20 v To estimate the "average" temperature in a city [in degrees F], you measure the temperature at a random sample of spots in the city. These values are shown in the table. 71.5 71 71.1 66.8 69.6 70.9 72 69.6 70 71.8 67.2 78.2 72.6 71.1 70.2 Build a 95% CI for the mean temperature in the city. You may assume that temperatures follow a normaL distribution. Keep at least 3 decimals in all intermediate steps, and round your answer to two decimals. Enter your Cl Like this: {min,max} Be sure to use the parentheses or you will be marked wrong. . Question 21 v In the past, trout in Clearwater Creek were 15.3 inches long on average. A recent sample of 40 trout from the creek found :7: = 17, 3 = 2.5. a. Build a 90% CI for the current mean length of trout in Clearwater Creek. Round all intermediate calculations to two decimals, then construct the CI and enter like this: {min,max}. Be sure to use parentheses or you will be marked wrong. Note: if you use a built-in Cl command on a calculator/computer, you might get marked wrong due to rounding. Use the formulas given in the textotes. b. Use your CI to decide whether the mean length of trout in Clearwater Creek has changed from 15.3 inches. C" No, the mean has not changed since the old value of p is right in the middle of the new CI {'1' Yes, the mean has probably changed since the new Cl does not contain the old value of u '5'33' Yes, the mean has probably changed since the old value of p is not right in the middle of the new Cl '33:? No, the mean has probably not changed since the new Cl contains the old value of p. 0 Question 22 v In the past, the mean age of students at a summer camp was 17.5 years old. A recent sample of 18 students from the camp found E = 12.5, 3 = 2.6. a. Build a 80% CI for the current mean age of students at the camp. Round all intermediate calculations to two decimals, then construct the Cl and enter like this: (min,max}. Be sure to use parentheses or you will be marked wrong. Note: if you use a built-in Cl command on a calculatorr'computer, you might get marked wrong due to rounding. Use the formulas given in the textr'notes. b. Use your CI to decide whether the mean age of students at the camp has changed from 17.5 years old. '3' No, the mean has not changed since the old value of ,u is right in the middle of the new Cl '33:? Yes, the mean has probably changed since the new Cl does not contain the old value of ,u '33:? Yes, the mean has probably changed since the old value of ,u is not right in the middle of the new Cl '33:? No, the mean has probably not changed since the new Cl contains the old value of ,u c. For this problem, it is important that we know that ages are normally distributed. This is because: '33:? we are using a Z-interval '33:} we are using 5 in place of 0' -::III:- n