Answer:
31.82% probability that this day would be a winter day
Step-by-step explanation:
We use the conditional probability formula to solve this question. It is
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
In which
P(B|A) is the probability of event B happening, given that A happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(A) is the probability of A happening
In this question:
Event A: Rain
Event B: Winter day
Probability of rain:
0.42 of 0.25(winter), 0.23 of 0.25(spring), 0.16 of 0.25(summer) or 0.51 of 0.25(fall).
So
[tex]P(A) = 0.42*0.25 + 0.23*0.25 + 0.16*0.25 + 0.51*0.25 = 0.33[/tex]
Intersection:
Rain on a winter day, which is 0.42 of 0.25. So
[tex]P(A \cap B) = 0.42*0.25 = 0.105[/tex]
If you were told that on a particular day it was raining in Vancouver, what would be the probability that this day would be a winter day?
[tex]P(B|A) = \frac{0.105}{0.33} = 0.3182[/tex]
31.82% probability that this day would be a winter day
