8-3 p394 n10
Original claim: using the YSORT method, the probability of a baby being a boy is greater than 50%
p > 0.5

The Null Hypothesis
H₀: p = 0.5

The Alternate Hypothesis
H₁: p > 0.5

A sample of n = 51 has 50 degrees of freedom.
For a right tailed test and a level of significance, α = 0.01
z_critical = 2.326

Data:
p^= 0.7647
z_test = (0.7647 - 0.5) ⁄ √0.5×0.5 ⁄ 51 = 3.781

Because 3.781 is IN the Critical Region, we Reject the Null Hypothesis and the statistical analysis of the data can support the original claim.

Conclusion:
The sample data SUPPORT the claim that using the YSORT method, the probability of a baby being a boy is greater than 50%