Question

Jillian surveyed students at her school and found out the following probabilities:

\begin{aligned} &P(\text{freshman})=0.30 \\\\ &P(\text{plays instrument})=0.20 \\\\ &P(\text{freshman and instrument})=0.10 \end{aligned}
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P(freshman)=0.30
P(plays instrument)=0.20
P(freshman and instrument)=0.10
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Find the probability that a student plays an instrument given they are a freshman.

Answer 1

Explanation:

Use conditional probability.

P(A given B) = P(A and B) / P(B)

P(instrument given freshman) = P(instrument and freshman) / P(freshman)

P(instrument given freshman) = 0.10 / 0.30

P(instrument given freshman) = 0.33