Stata Technical Bulletin
25
. npt_s r_area if quit~=O, by(quit)
|
quit |
score |
obs |
sum of ranks |
|
1.0 |
1.0 |
19 |
1062.ε |
|
2.0 |
2.0 |
13 |
638. ε |
|
3.0 |
3.0 |
ιε |
εo8.ε |
|
4.0 |
4.0 |
11 |
267.0 |
|
ε.o |
ε.o |
17 |
373. ε |
|
Obs |
Exp Var | ||
|
6800.ε |
8322.0 79672 |
z = -ε.39, chi-squared(l) = 29.09
P>∣z∣ = 0.0000
It is likely that women of social classes 1 and 2 will have been more successful in giving up smoking.
|
. tab quit sc3 if quit~=0, row | ||||
|
Smokingl Social Class |
3-5 I |
Total | ||
|
change I |
1 |
2 | ||
|
>76 I I |
6 31.58 |
4 21.05 |
9 I 47.37 I |
— 19 100.00 |
|
(.5,75] I |
3 23.08 |
5 38.46 |
5 I 38.46 I |
— 13 100.00 |
|
(.2s,.εj I |
0 |
13 86.67 |
2 I 13.33 I |
— 15 100.00 |
|
(0,.26] I |
5 45.45 |
5 45.45 |
1 I 9.09 I |
— 11 100.00 |
|
quit I I |
6 35.29 |
9 52.94 |
2 I 11.76 I |
— 17 100.00 |
|
Total I I |
20 26.67 |
36 48.00 |
19 I 25.33 I |
— 75 100.00 |
|
. npt_s sc3 if 1.0 2.0 3.0 4.0 5.0 |
quit^=0 score 1.0 2.0 3.0 4.0 5.0 |
by(quit) 19 13 15 11 17 Obs 7768.0 |
sum of ranks 811.0 554.0 632.5 311.0 541.5 Exp 8322.0 |
Var 79572 |
z = -1.96, chi-squared(l) = 3.86
P>∣z∣ = 0.0495
It is important to make sure that the observed association between smoking reduction and change in lesion size is not
confounded by the amount that the women smoked at the beginning of the study.
. tab quit init if quit"=0, row
|
Smoking I |
Initial No./day |
21+ I |
Total | |
|
1-10 |
11-20 | |||
|
>75 I I |
4 21.05 |
10 52.63 |
5 I 26.32 I |
— 19 100.00 |
|
(.5,75] I |
0 |
5 38.46 |
8 I 61.54 I |
— 13 100.00 |
|
(.25,.5] I I |
3 20.00 |
10 66.67 |
2 I 13.33 I |
— 15 100.00 |
|
(0,.25] I I |
7 63.64 |
4 36.36 |
0 I 0.00 I |
— 11 100.00 |
|
— — ——— — ——— — —-f-- I |
8 47.06 |
8 47.06 |
i I 5.88 I |
— 17 100.00 |