Posted by Kayla on .
If the probability of a newborn child being female is 0.5, find the probability that in 100 births, 55 or more will be female. Use the normal distribution to approximate the binomial distribution.

Statistics 
MathGuru,
Mean = np
Standard deviation = √npq
Note: q = 1  p
n = 100
p = 0.5
q = 0.5
Once you find the mean and standard deviation, use zscores:
z = (x  mean)/sd
(x = 55)
Check a ztable to find the probability using the zscore you calculated. 
Statistics 
Jane,
54.550/50 = 4.5/5 = 0.9 z= 0.1841