16. The partial pressure of oxygen, PaO2, is a measure of the amount of oxygen in the blood. Assume that the distribution of PaO2 levels among newborns has an average of 38 mm Hg and a standard deviation of 9, and that these readings have a normal distribution. What proportion of PaO2 readings are greater than 35 but less than 40 mm Hg? 17. The cholesterol level in healthy individuals is age and gender dependent. For males under the age of 21, the average reading is 162.3 mg/dl with a standard deviation of 11.8 mg/dl. Assume that these cholesterol levels are normally distributed. A simple random sample of 12 males under the age of 21 is taken. Calculate the probability that their mean cholesterol level is more than 170 mg/dl. 18. The reported cancer rates for men ages 65 and older is 23%. Assume this estimate is the true population proportion of men ages 65 and older who have been diagnosed with some form of cancer. A SRS of 25 men ages 65 and older is taken. Calculate the probability that proportion of men ages 65 and older who have been diagnosed with some form of cancer is more than 0.30. 19. A hospital would like to determine the average length of stay for its patients having abdominal surgery. A simple random sample of 20 patients who had abdominal surgery found a sample mean length of stay of 7.1 days and a sample standard deviation of 1.3 days. Assume that the length of stay after abdominal surgery is normally distributed. A 90% confidence interval is to be constructed based on this data. What is the value of the margin of error for this confidence interval