document.write( "Question 967562: According to police sources, a car with a certain protection system will be recovered 90% of the time.
\n" ); document.write( "1)If 12 of these stolen cars are randomly selected, find the probability that exactly four will be recovered? (find numerical value).
\n" ); document.write( "2)if 100 of these cars are stolen use normal distribution to approximate the probability of recovering at least 60 of them?
\n" ); document.write( "3)if 100 of these cars are stolen what is the expected value and standard deviation of the number of cars recovered ? \n" ); document.write( "
Algebra.Com's Answer #591414 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
According to police sources, a car with a certain protection system will be recovered 90% of the time.
\n" ); document.write( " 1)If 12 of these stolen cars are randomly selected, find the probability that exactly four will be recovered? (find numerical value).
\n" ); document.write( "P(x=4) = 12C4*0.9^4*0.1^8 = binompdf(12,0.9,4) = 0.000003247
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\n" ); document.write( " 2)if 100 of these cars are stolen use normal distribution to approximate the probability of recovering at least 60 of them?
\n" ); document.write( "mean = np = 90
\n" ); document.write( "std = sqrt(npq) = sqrt(90*0.1) = sqrt(9) = 3
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\n" ); document.write( "z(59) = (59-90)/3 = -10.33
\n" ); document.write( "P(x >= 60) = P(z>= -10.33) = normalcdf(-10.33,100) = 1
\n" ); document.write( "-------------------------
\n" ); document.write( " 3)if 100 of these cars are stolen what is the expected value and standard deviation of the number of cars recovered ?
\n" ); document.write( "mean = np = 0.9*100 = 90
\n" ); document.write( "std = sqrt(npq) = 3
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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