Introductory Biostatistics

7.13 Treatment:x 1 ¼ 701 :9,s 1 ¼ 32 :8; control:x 2 ¼ 656 :1,s 2 ¼ 22 :5.

sp¼ 29 : 6

t¼ 3 : 45 ;17 df; p< 0 : 01

7.14 sp¼ 9 : 3

t¼ 4 : 71 ; pF 0

7.15 Weight gain:sp¼ 14 : 4

t¼ 2 : 30 ; p< 0 : 05

Birth weight:sp¼ 471 : 1

t¼ 2 : 08 ; p< 0 : 05

Gestational age:sp¼ 15 : 3

tF 0 ; pF 0 : 5

7.16 Sum of ranks: bulimic adolescents, 337.5; healthy adolescents, 403.5.

mH¼

ð 15 Þð 15 þ 23 þ 1 Þ

2

¼ 292 : 5

sH¼

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

ð 15 Þð 23 Þð 15 þ 23 þ 1 Þ

12

r

¼ 33 : 5

z¼

403 : 5
292 : 5

33 : 5

¼ 3 : 31 ; pF 0

7.17 Sum of ranks: experimental group, 151; control group, 39.

mE¼

ð 12 Þð 12 þ 7 þ 1 Þ

2

¼ 120

sE¼

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

ð 12 Þð 7 Þð 12 þ 7 þ 1 Þ

12

r

¼ 11 : 8

z¼

151
120

11 : 8

¼ 262 ; p¼ 0 : 0088

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