|
| Conditioned | Total | |
|
| Yes = +1 | No = +0 | |
Condition | Yes = +1 | a = 0 | b | (a + b) |
No = +0 | c | d = 0 | (c + d) | |
| Total | (a + c) | (b + d) | (a + b + c + d) |