The idea
“Given” means “look only at this group”
| Subscribes | Doesn't | Total | |
|---|---|---|---|
| Women | 120 | 372 | 492 |
| Men | 244 | 288 | 532 |
| Everyone | 364 | 660 | 1,024 |
The chance a man subscribes: ignore the women, look only at the men's row, 244 of 532.
P(subscribes | man) = 244 / 532 = 0.459
The bar “|” is read as “given”. Given = zoom into that group only.