Question

If 23% of the families with 8 children who took GenPiks medication have over 6 girls is it reasonable to conclude that the medication significantly increases a couple's chance of having girls. Explain.

Answer 1

Let us assume that the chance of having a boy and a girl is equal to 0.5 each

Thus, Probability of having over 6 girls in 8 children = P(X = 7) + P(X = 8)

= 0.03516 = 3.516%

Thus, the maximum standard error = =

As the sample size, n would be high (atleast 30), the standard error gets lowered.

So, the corresponding z value = which is approximately

This implies that the z value corresponding to 23% is very high which cannot occur by chance.

Thus, it is reasonable to conclude that the medication significantly increases a couple's chance of having girls.