Solutions for session 6, Part B

See solutions for Problems: B1 | B2 | B3

 Problem B1 The raisin studies are observational because they observe the objects (raisins) as they are. There is no treatment deliberately imposed on any group of raisins, so there is no "cause and effect" to study.

Problem B2

Here are the Five-Number Summaries and box plots for each brand:

Min

Q1

Med

Q3

Max

 Brand A 23 27 29.5 32 39 Brand D 23 27 29 33 38

The box plots indicate that the two sets of counts are very similar. The location indicators are all about the same: The Mins and Q1s are exactly the same, and the Meds, Q3s, and Maxes differ by 0.5, 1, and 1, respectively, which are not large differences relative to the magnitudes of the numbers we are comparing.

The degree of variation is similar for the two brands. The ranges for Brands A and D are 16 and 15, respectively, and the IQRs are 5 and 6.

Problem B3

Here are the Five-Number Summaries for each brand:

Min

Q1

Med

Q3

Max

 Brand A 23 27 29.5 32 39 Brand B 17 25 26 29 30 Brand C 25 26 28 29 32

The Five-Number Summaries for Brands A, B, and C suggest that Brand B has the fewest raisins in general. It has the smallest median (26), the smallest minimum (17), and the smallest maximum (30). Brand C has the least total variation and the highest minimum (25). Brand A has the most raisins in general, having the largest median (29.5) and by far the largest maximum (39); it also has the greatest variation.