Chapter 9, Problem 13 (plus)

Use the dataset lowbwt on the CD that came with the textbook.

a. Compute a 95% confidence interval for the true mean systolic blood pressure of male low birth weight infants.

b. Compute a 95% confidence interval for the true mean systolic blood pressure of female low birth weight infants.

c. Do you think it's possible that males and females have the same mean systolic blood pressure? Explain briefly.

Answer:

d. Calculate 90% confidence intervals for both male and female low birth weight infants (two separate intervals).

e. Calculate a 99% confidence interval for both male and female low birth weight infants (two separate intervals).

f. Suppose the standard deviation () of the larger population of low birth weight infants is 11 mm. Construct 95% confidence intervals for males and females. You will likely need to use software to get the sample mean (x-bar) values.

g. How does the interval calculated based on differ from the 95% interval based on s?