Question

1) High blood pressure has been identified as a risk factor for heart attacks and strokes. The proportion of U.S. adults with high blood pressure is 0.3. A sample of 81 U.S. adults is chosen.

a) What is the sampling distribution of?

pˆ

b) Find the probability that the proportion of individuals in the sample who have high blood pressure is between 0.24 and 0.35.

c) Find the probability that less than 26% of the people in the sample have high blood pressure.

d) Find the probability that more than 28% of the people in the sample have high blood pressure.

e) Would it be unusual if more than 31% of the individuals in the sample of 81 had high blood pressure? Explain.

2) Researchers obtained the body temperature of 93 healthy humans and found the average body temperature of these 93 people to be 97.3°F. Construct a 99% confidence interval for the population mean body temperature of healthy humans. Assume σ = 0.63°F. Interpret your result.

3) A firm would like to estimate the mean age of all people in the civilian labor force. What size sample would be required to estimate the mean age of all people in the civilian labor force accurate to within 0.75 year of the estimate at the 95% confidence level, given that σ = 15.26 years?

4) The average monthly electric bill of a random sample of 35 residents of a city is $90 with a standard deviation of $24. Construct a 98% confidence interval for the population monthly electric bills of all residents. Interpret your result.

Answer 1