A certain reaction was run several times using each of two catalysts, A and B. The catalysts were supposed to control the yield of an undesirable side product. Results, in units of percentage yield, for 24 runs of catalyst A and 20 runs of catalyst B are as follows:

Question

a. Construct a histogram for the yields of each catalyst.

b. Construct comparative boxplots for the yields of the two catalysts.

c. Using the boxplots, what differences can be seen between the results of the yields of the two catalysts?

Answer 1

(a) Here are histograms for each group. Other choices for the endpoints are possible.





(b)





(c) The yields for catalyst B are considerably more spread out than those for catalyst A.The median yield for catalyst A is greater than the median for catalyst B. The median yield for B is closer to the first quartile than the third, but the lower whisker is longer than the upper one, so the median is approximately equidistant from the extremes of the data. Thus the yields for catalyst B are approximately symmetric. The largest yield for catalyst A is an outlier; the remaining yields for catalyst A are approximately symmetric.