The paper "Relationship Between Blood Lead and Blood Pressure Among Whites and African Americans" (a technical report published by Tulane University School of Public Health and Tropical Medicine, 2000) gave summary quantities for blood lead level (in micrograms per deciliter) for a sample of whites and a sample of African Americans. Data consistent with the given summary quantities follow:
a. Compute the values of the mean and the median for blood lead level for the sample of African Americans.
b. Which of the mean or the median is larger? What characteristic of the data set explains the relative values of the mean and the median?
c. Construct a comparative boxplot for blood lead level for the two samples.
d. Write a few sentences comparing the blood lead level distributions for the two samples.