8-3 p394 n18
Original claim: the proportion of deaths in the week before Thanksgiving is less than 0.5
p < 0.5

The Null Hypothesis
H₀: p = 0.5

The Alternate Hypothesis
H₁: p < 0.5

A sample of n = 12000 has 11999 degrees of freedom.
For a left tailed test and a level of significance, α = 0.05
z_critical = -1.645

Data:
p^= 0.5052
z_test = (0.5052 - 0.5) ⁄ √0.5×0.5 ⁄ 12000 = 1.139

Because 1.139 is NOT in the Critical Region, we Fail to Reject the Null Hypothesis and the statistical analysis of the data can NOT support the original claim.

Conclusion:
There is NOT sufficient sample evidence to support the claim that the proportion of deaths in the week before Thanksgiving is less than 0.5