J :3d. In a Public Health Service Study of 1964, a histogram was plotted showing the number of cigarettes per day smoked by each subject (male, current smokers), as shown in diagram ? on page ? of the test. The density is marked in parentheses. The class intervals include the right endpoint, not the left.
a. 0.35 of 1% b. 0.5 0f 1% c. 1.5% d. 3.5% e. 10%