document.write( "Question 442455: This problem is really difficult. Please show me how to solve it:\r
\n" ); document.write( "\n" ); document.write( "14. On average, a telemarketer makes one sale in every six calls. If she makes 180 calls, find the probability that she will make at least 38 sales. (Use normal approximation, 4 digits after decimal point.)
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Algebra.Com's Answer #305166 by stanbon(75887)\"\" \"About 
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On average, a telemarketer makes one sale in every six calls. If she makes 180 calls, find the probability that she will make at least 38 sales. (Use normal approximation, 4 digits after decimal point.)
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\n" ); document.write( "Binomial Problem
\n" ); document.write( " with n = 180 and p = 1/6
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\n" ); document.write( "P(38<= x <=180) = ?
\n" ); document.write( "mean = np = 180*(1/6) = 30
\n" ); document.write( "std = sqrt(npq) = sqrt(30*(5/6)) = 5
\n" ); document.write( "Using normal approximation, find P(37.5 <= x <=180.5)
\n" ); document.write( "z(37.5) = (37.5-30)/[5] = 1.5
\n" ); document.write( "z(180.5) = (180.5-30)/(5) = 10.1
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\n" ); document.write( "So, P(38<= x <=180) = P(1.5<= z<=10.1) = 0.0668
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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