3.70 ● Many nutritional experts have expressed concern about the high levels of sodium in prepared foods. The following data on sodium content (in milligrams) per frozen meal appeared in the article

“Comparison of ‘Light’ Frozen Meals” (Boston Globe, April 24, 1991):

720 530 800 690 880 1050 340 810 760 300 400 680 780 390 950 520 500 630 480 940 450 990 910 420 850 390 600 Two histograms for these data are shown on the next page.

a. Do the two histograms give different impressions about the distribution of values?

b. Use each histogram to determine approximately the proportion of observations that are less than 800, and compare to the actual proportion.