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.
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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.