In: Statistics and Probability
Two doctors, Dr. Johnson and Dr. Chris, at a health care center are researching the effects of high blood pressure for senior citizens (60 - 65 years old) in Brazos County. There are total 2216 senior citizens (60 - 65 years old) in Brazos County (the data is fictional).
During the process:
Dr. Johnson measures the blood pressure for 10 elderly patients, with an average blood pressure 131.31 mmHg and a sample deviation of 14.99 mmHg.
Dr. Chris measures the blood pressure for 80 elderly patients, with an average blood pressure 127 mmHg and a sample deviation of 20.00 mmHg.
If the blood pressure is higher than 140 mmHg, it is considered to be high blood pressure. Assume that patient measurements are normally distributed.
a) How confidence is Dr. Johnson that the average of the senior citizens’ blood pressure is less than 140?
b) Based on the data obtained by Dr. Chris, estimate the number of senior citizens (60 - 65 years old in the Brazos County) who has high blood pressure. List all your assumptions.