Question

Find P(Y|B) from the information in the table.

| X | Y |Z | total
a | 8 | 80 | 40 | 128
b | 6 | 34 | 45 | 85
c | 23 | 56 | 32 | 111
total | 37 | 170 | 117 | 324

To the nearest tenth, P(Y|B) =____

Answer 1

34/85

Explanation:

Answer 2

P(Y|B) reads 'Probability of event Y happening given event B is happening'. This is a conditional probability and the formula is given as

P(Y|B) = P(Y∩B) / P(B)

From the table, P(Y∩B) = 34/324 and P(B) = 85/324

Hence,
P(Y|B) = (34/324) ÷ (85/324) = 34/85