9.4 (a) The total of the entire table is 14050 (thousands). (b) 246/14050 = 1.75%. (c) Dividing the 22-34 row by its total gives the following percents. We see from the graph that most of these are in 4yr, FT and the fewest (10%) are in 2 yr, FT schools.

2yr, FT	2yr, PT	4yr, FT	4yr, PT
10.8	26.9	38.7	23.6

(d) The following is the percent of each program that are in the 18-21 age group. In the FT programs, this age group is over 50% of the enrollment. In the 2 yr PT group, it accounts for 20%, but is <10% of the 4yr PT enrollment.

2yr, FT	2yr, PT	4yr, FT	4yr, PT
55.8	20.5	54.5	8.7

9.5 The marginal distribution for type is the bottom row divided by the overall total (14050). This shows that 4 yr FT programs dominate, with the other programs gradually decreasing.

9.6 The counts and totals are given below.

	2yr	4yr	Total
FT	2017	6002	8019
PT	3476	2555	6031
Total	5493	8557	14050

The distribution by time (percents) is below. Full time colleges are predominantly 4 yr programs, while part time colleges are evenly split between 2 yr and 4 yr.

	2yr	4yr
FT	25.2	74.8
PT	57.6	42.4

9.7 The conditional distribution is found by dividing each entry by the total for the type of institution (the column total).

	2yr, FT	2yr, PT	4yr, FT	4yr, PT	Total
<18	1.8	2.8	1.2	1.4	7.3
18-21	55.8	20.5	54.5	8.7	139.5
22-34	31.4	45.3	37.8	54.0	168.5
35 up	11.0	31.4	6.5	35.8	84.7

Both 2 yr and 4 yr FT schools are dominated by 18-21 yr olds. Both 2 yr and 4 yr PT schools have mostly 22-34 and 35 up students.