document.write( "Question 52671: A small town has 5,600 residents. The residents in the town were asked whether or not they favored building a new bridge across the river. You are given the following information on the residents' responses, broken down by sex.
\n" ); document.write( " Men Women Total
\n" ); document.write( "In Favor 1,400 280 1,680
\n" ); document.write( "Opposed 840 3,080 3,920
\n" ); document.write( "Total 2,240 3,360 5,600\r
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\n" ); document.write( "\n" ); document.write( " Let: M be the event a resident is a man
\n" ); document.write( " W be the event a resident is a woman
\n" ); document.write( " F be the event a resident is in favor
\n" ); document.write( " P be the event a resident is opposed\r
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\n" ); document.write( "\n" ); document.write( " a. Find the joint probability table.
\n" ); document.write( " b. Find the marginal probabilities.
\n" ); document.write( " c. What is the probability that a randomly selected resident is a man and is in favor of building the bridge?
\n" ); document.write( " d. What is the probability that a randomly selected resident is a man?
\n" ); document.write( " e. What is the probability that a randomly selected resident is in favor of building the bridge?
\n" ); document.write( " f. What is the probability that a randomly selected resident is a man or in favor of building the bridge?
\n" ); document.write( " g. A randomly selected resident turns out to be male. Compute the probability that he is in favor of building the bridge.
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Algebra.Com's Answer #35520 by stanbon(75887)\"\" \"About 
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Men Women Total
\n" ); document.write( "In Favor 1,400 280 1,680
\n" ); document.write( "Opposed 840 3,080 3,920
\n" ); document.write( "Total 2,240 3,360 5,600\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( " Let: M be the event a resident is a man
\n" ); document.write( " W be the event a resident is a woman
\n" ); document.write( " F be the event a resident is in favor
\n" ); document.write( " P be the event a resident is opposed\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " a. Find the joint probability table.
\n" ); document.write( "Need figure prob of M&F, W&F, M&O, W&O
\n" ); document.write( "For example P(M&F)=1400/5600=0.25
\n" ); document.write( " b. Find the marginal probabilities.
\n" ); document.write( "Nee figure Prob of M, of W, of F, or O
\n" ); document.write( "For example P(M)=3920/5600=0.70
\n" ); document.write( " c. What is the probability that a randomly selected resident is a man and is in favor of building the bridge?
\n" ); document.write( "Prob(M&F)= 0.25 as we figured above
\n" ); document.write( " d. What is the probability that a randomly selected resident is a man?
\n" ); document.write( "P(M)=3920/5600=0.70
\n" ); document.write( " e. What is the probability that a randomly selected resident is in favor of building the bridge?
\n" ); document.write( "P(F)=1680/5600=0.30
\n" ); document.write( " f. What is the probability that a randomly selected resident is a man or in favor of building the bridge?
\n" ); document.write( "P(M or F)= P(M)+P(F)-P(M&f)= [3920+1680-1400]/5600=4200/5600=0.75
\n" ); document.write( " g. A randomly selected resident turns out to be male. Compute the probability that he is in favor of building the bridge.
\n" ); document.write( "P(F|M)= 1400/2240=0.625\r
\n" ); document.write( "\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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