SOLUTION: Use normal approximation to estimate the probability of getting less than 48 girls in 100 births. Assume that boys and girls are equally likely.

Question 286569: Use normal approximation to estimate the probability of getting less than 48 girls in 100 births. Assume that boys and girls are equally likely.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Use normal approximation to estimate the probability of getting less than 48 girls in 100 births. Assume that boys and girls are equally likely.
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binomial P(0<= x <=48)
normal appox = P(-0.5<= x <=48.5)
mean = np = 100(1/2) = 50
std = sqrt(npq) = sqrt(50(1/2)) = sqrt(25) = 5
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z(-0.5) = (-0.5-50)/5 = -10.1
z(48.5) = (48.5-50)/5 = -0.3
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P(-10.1<= z <=-.3) = 0.3821
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Cheers,
Stan H.
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