:2. Diagram ? on page ? shows a histogram for the blood
pressures of subjects in a certain survey, along with the normal
curve which approximates it. The percentage who had blood
pressures between 120mm and 140mm is exactly equal to
a. 40%
b. the area under the histogram between 120 and 140
c. the area under the normal curve between 120 and 140
d. 100%
e. 0%