document.write( "Question 230588: Consider a binomial distribution with 15 identical trials, and a probability of success of 0.5. Find the probability that x = 3 using the binomial tables. Use the normal approximation to find the probability that x = 3. Show all work. \n" ); document.write( "
Algebra.Com's Answer #170756 by stanbon(75887)\"\" \"About 
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Consider a binomial distribution with 15 identical trials, and a probability of success of 0.5. Find the probability that x = 3 using the binomial tables.
\n" ); document.write( "P(x=3) = 15C3(0.5)^3*(0.5)^12 = 0.0139..
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\n" ); document.write( "Use the normal approximation to find the probability that x = 3. Show all work.
\n" ); document.write( "Note: mean = np = 15*0.5 = 7.5 ; std = sqrt(npq) = sqrt(7.5*0.5) = 1.9365..
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\n" ); document.write( "P(x=3) = P(2.5 < x < 3.5)
\n" ); document.write( "z(2.5) = (2.5-7.5)/1.9365 = -2.5820
\n" ); document.write( "z(3.5) = (3.5-7.5)/1.9365 = -2.0656
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\n" ); document.write( "P(2.5 < x < 3.5) = P(-2.5820 < z < -2.0656) = 0.0145
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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