Vitamin C and colds
One group of 139 skiers was given 1 gram ascorbic acid (vitamin C) per day and another group of 140 was given a placebo. Which skiers got colds?
|
Cold |
No cold |
Ascorbic acid |
17 |
122 |
Placebo |
31 |
109 |
Drug screening of US postal service job applicants
The test results are shown separately for males and females below.
|
Negative |
Marijuana |
Cocaine |
Other drugs |
Total |
Male |
1465 |
146 |
33 |
28 |
1672 |
Female |
764 |
52 |
22 |
27 |
865 |
Drug screening of job applicants
In this contingency table, the applicants are grouped by the amount of exercise they take.
|
Negative |
Marijuana |
Cocaine |
Other drugs |
Total |
Aerobic |
301 |
28 |
5 |
6 |
340 |
Non-aerobic |
736 |
58 |
18 |
14 |
826 |
None |
1182 |
112 |
32 |
35 |
1361 |