High blood pressure has been identified as a risk factor for heart attacks and strokes. The National Health and Nutrition Examination Survey reported that the proportion of U. S. adults with high blood pressure is 0.3. A sample of 38 U. S. adults is chosen. (a) Is it appropriate to use the normal approximation to find the probability that more than 40% of the people in the sample have high blood pressure. If so, find the probability. If not, explain why not.
B. A new sample of 80 adults is drawn. Find the probability that more than 40% of the people in this sample have high blood pressure.
C. Find the probability that the proportion of individuals in the sample of 80 who have high blood pressure is between 0.20 and 0.35.
D. Find the probability that less than 25% of the people in the sample of 80 have high blood pressure.
E. Would it be unusual if more than 45% of the individuals in the sample of 80 had high blood pressure?