In: Statistics and Probability
Eighty-five percent of UCD students are Irish. Forty percent of UCD students play rugby. Thirty five percent of students are Irish and play rugby. If a student is selected at random, find the conditional probability that:
(a) the student practices rugby, given that the he/she is Irish;
(b) the student is Irish, given that the he/she practices rugby. List all the properties/theorems you have used in your calculations.
P(Irish) = 0.85
P(play rugby) = 0.4
P(Irish and play rugby) = 0.35
a) P(play rugby | Irish) = P(Irish and play rugby) / P(Irish)
= 0.35 / 0.85
= 0.4118
b) P(Irish | play rugby) = P(Irish and play rugby) / P(play rugby)
= 0.35 / 0.4
= 0.875