StatisticsdrillTotal probability across groups
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
An online store ships with three carriers. Carrier A handles 20% of orders, B 17% and C 63%. Their late delivery rates are 12%, 9% and 7%. What is the probability that a randomly chosen order arrives late? Round to 4 decimal places.
What this problem teaches
The formula: P(late) = Σ P(carrier) × P(late | carrier).
A hint if you get stuck
Weight each carrier's late rate by its share of orders, then add.
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