A back-to-back stem-and-leaf plot compares two data sets by using the same stems for each data set. Leaves for the first data set are on one side while leaves for the second data set are on the other side.The back-to-back stem-and-leaf plot shows the salaries (in thousands) of all lawyers at two small law firms.

Key: 5 | 19 | 0=$195,000 for Law Firm A and $190,000 for Law Firm B

Law Firm A		Law Firm B
7 1	9	1 2
9 4 2 2 2	10	4 8
9 9 6 0 0	11	0 0 4
1 1	12	0 2 2 5

13 2 5 5 9

14 1 3 3 3 8

15 5 5 5 6

16 4 9 9

9 9 5 1 0	17	1 2 5
5 5 5 3 2	18	9
9 9 8 7 4	19	5
4	20

(a) What are the lowest and highest salaries at Law Firm A? at Law Firm B?

At Law Firm A the lowest salary was $ ____ and the highest salary was $ _____.

At Law Firm B the lowest salary was $ ____ and the highest salary was $ ____.

(b) How many lawyers are in each firm?

There are ____ lawyers at Law Firm A and _____ lawyers at Law Firm B.

(c) Compare the distribution of salaries at each law firm. What do you notice?

A.At Law Firm A the salaries tend to fall in the middle of the distribution range and at Law Firm B the salaries tend to be clustered at the far ends of the range.

B.The salaries of both firms are identically distributed in the distribution range.

C.The salaries of both firms are clustered at the opposite ends of their distribution range.

D.At Law Firm B the salaries tend to fall in the middle of the distribution range and at Law Firm A the salaries tend to be clustered at the far ends of the range.