Official answer:
1) Since the bars are arranged in order from greatest to least, the median will be the average of the heights of Bars E and F. The height of Bar E is 1.1 and the height of Bar F is less than 1.1, so the average of the heights of the two bars is less than 1.1.
2) First, since the mean, by definition, is the sum of all the data values in the data set divided by the number of data values, it would be useful to estimate the sum of the heights of the bars representing the amounts per serving of Substance X in the 10 commercially available food products containing the greatest per-serving amounts of Substance X. Observe that the heights of Bars B and C appear to be 1.4. Both Bar D and Bar E are shorter than 1.4 and while Bar A appears to be taller than 1.4 by 0.2, Bar E appears to be shorter than 1.4 by 0.3, so estimating the heights of Bars A–E as 1.4 ensures that the sum of their heights is less than 5(1.4) = 7.0. Estimating the heights of each of Bars F–J as 1.0 ensures that the sum of their heights is less than 5(1.0) = 5. Thus, the sum of the heights of the bars representing the amounts per serving of Substance X in the 10 commercially available food products containing the greatest per-serving amounts of Substance X is less than 7.0 + 5.0 = 12.0.
If N is the number of commercially available products that contain Substance X, then N > 400. Let n be the number in excess of 400 so N = 400 + n. The heights of Bars A–J, in order, represent the amounts per serving, in milligrams, of Substance X in the 10 commercially available food products containing the greatest per-serving amounts of Substance X and the sum of these heights is less than 12. The least of these heights is about 0.71, so the rest of the (400 + n) − 10 = 390 + n commercially available food products containing Substance X have at most 0.71 mg of Substance X each. In the worst case, the mean of all of the per-serving amounts of Substance X in commercially available products would be at most
then the mean is less than 0.8.