StatisticsdrillConditional probability from P(A and B)
A statistics problem from Statisticsdrill. Solve it with one answer box, with a fresh sample on every attempt and the worked steps and spreadsheet function in the answer, and it is checked the moment you submit.
The task
In a survey, 20% of customers use the mobile app, and 15% both use the mobile app and have a premium plan. Given that a randomly chosen customer is one who uses the mobile app, what is the probability that they also have a premium plan? Round to 4 decimal places.
What this problem teaches
The formula: P(A | B) = P(A and B) / P(B). Conditioning shrinks the sample space to the group named after 'given that', so the answer is larger than P(A and B).
A hint if you get stuck
P(A | B) = P(A and B) / P(B). Divide the share with both by the share of the group you are told the person is in.
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