A simple random sample of 50 adults (including males and females) is obtained, and each person’s red blood cell count (in cells per microliter) is measured. The sample mean is 4.63. The population standard deviation for red blood cell counts is 0.54.

a. Find the best point estimate of the mean red blood cell count of adults.

b. Construct a 99% confidence interval estimate of the mean red blood cell count of adults.

c. The normal range of red blood cell counts for adults is given by the National Institutes of Health as 4.7 to 6.1 for males and 4.3 to 5.4 for females. What does the confidence interval suggest about these normal ranges?