Chapter 4, Problem 4.6P

Compute the standard deviation for the pretest and posttest scores that were used in problems 2.6 and 3.12. The scores are reproduced here. Taking into account all of the information you have on these variables, write a paragraph describing how the sample changed from test to test. What does the standard deviation add to the information you already had?

Case	Pretest	Posttest
A	8	12
B	7	13
C	10	12
D	15	19
E	10	8
F	10	17
G	3	12
H	10	11
I	5	7
J	15	12
K	13	20
L	4	5
M	10	15
N	8	11
O	12	20

2.6 $\boxed{SW}$ A local youth service agency has begun a sex education program for teenage girls who have been referred by the juvenile courts. The girls were given a 20-item test for general knowledge about sex, contraception, and anatomy and physiology upon admission to the program and again after completion of the program. The scores of the first 15 girls to complete the program are as follows.

Case	Pretest	Posttest	Case	Pretest	Posttest
A	8	12	I	5	7
B	7	13	J	15	12
C	10	12	K	13	20
D	15	19	L	4	5
E	10	8	M	10	15
F	10	17	N	8	11
G	3	12	O	12	20
H	10	11

3.12 $\boxed{SW}$ Compute the median and mean for both the pretest and posttest for the test scores first presented in problem 2.6 and reproduced here. Interpret the statistics.

Case	Pretest	Posttest
A	8	12
B	7	13
C	10	12
D	15	19
E	10	8
F	10	17
G	3	12
H	10	11
I	5	7
J	15	12
K	13	20
L	4	5
M	10	15
N	8	11
O	12	20