/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 19 The 1992 U.S. Senate was compose... [FREE SOLUTION] | 91Ó°ÊÓ

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The 1992 U.S. Senate was composed of 57 Democrats and 43 Republicans. Of the Democrats, 38 served in the military, whereas 28 of the Republicans had seen military service. If a senator selected at random had served in the military, what is the probability that he or she was Republican?

Short Answer

Expert verified
The probability that a senator selected at random with military service is a Republican is approximately 42.4%. \(P(Republican | Military Service) ≈ 0.424\)

Step by step solution

01

Understand the question

We need to find the probability that a randomly chosen senator with military service is Republican. In other words, we need to find the value of the conditional probability P(Republican | Military Service).
02

Calculate the probabilities

First, let's find the probability of selecting a Republican Senator, a Democrat Senator, a Senator who served in the military, and a Senator who did not serve in the military. - Total Number of Senators = 57 Democrats + 43 Republicans = 100 - P(Republican) = Number of Republicans / Total Number of Senators = 43 / 100 - P(Democrat) = Number of Democrats / Total Number of Senators = 57 / 100 - P(Military Service) = (38 Democrats with Military Service + 28 Republicans with Military Service) / Total Number of Senators = (38 + 28) / 100 = 66 / 100 - P(No Military Service) = (57 Democrats - 38 Democrats with Military Service + 43 Republicans - 28 Republicans with Military Service) / Total Number of Senators = (19 + 15) / 100 = 34 / 100
03

Calculate the conditional probabilities

Next, we'll calculate the conditional probabilities that we need for our final calculation. - P(Military Service | Republican) = Number of Republican Senators with Military Service / Total Number of Republicans = 28 / 43 - P(Military Service | Democrat) = Number of Democrat Senators with Military Service / Total Number of Democrats = 38 / 57
04

Use the Bayes' theorem to find the required probability

We can use the Bayes' theorem to find the probability of a senator being a Republican given that they served in the military. Bayes' theorem formula: P(A | B) = (P(B | A) * P(A)) / P(B) In our case, we want to find P(Republican | Military Service). Therefore, A = Republican and B = Military Service. Using the Bayes' theorem, we have: P(Republican | Military Service) = (P(Military Service | Republican) * P(Republican)) / P(Military Service) Plugging in the values, we get: P(Republican | Military Service) = ((28 / 43) * (43 / 100)) / (66 / 100)
05

Calculate the final probability

Now we can calculate the final probability: P(Republican | Military Service) = (28 / 43) * (43 / 66) = 28 / 66 ≈ 0.424 So the probability that a senator selected at random with military service is a Republican is approximately 42.4%.

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