Question

A magazine subscription service has surveyed 1462 people who subscribe to its most popular fashion magazines. It has found that the probability that a person subscribes to "Style Bible" is 0.45, the probability a person subscribes to 'Runway' is 0.25 and the probability a person has subscriptions to both magazines is 0.20. Using a contingency table or otherwise, determine the probability that a person has a subscription to "Style Bible" given that they has a subscription to "Runway". Give the answer to two decimal places, in the form x.xx

Answer 1

Solution:

Given:

N = Sample size = Number of people surveyed who subscribe to its most popular fashion magazines = 1462

P( a person subscribes to "Style Bible" ) = P( S) = 0.45

P( a person subscribes to 'Runway' )= P( R) = 0.25

P( a person has subscriptions to both magazines ) = P( S and R) = 0.20

We have to find: the probability that a person has a subscription to "Style Bible" given that they has a subscription to "Runway".

That is: P( S | R) = .........?

Using conditional rule of probability:

Thus the probability that a person has a subscription to "Style Bible" given that they has a subscription to "Runway" is 0.80 .