Two Sample Z Test For Difference In Proportions
Two Sample Z Test For Difference In Proportions. Suppose we want to know if there is a difference in the proportion of residents who support a certain law in county a compared to the proportion who support the law in county b. Where z α/2 is the critical value of the normal distribution at α/2 (e.g.

X 1 and x 2 are number of trails;
For a confidence level of 95%, α is 0.05 and the critical value is 1.96), z β is the critical value of the normal distribution at β (e.g. N1 and n2 are sample sizes; Suppose the acme drug company develops a new drug, designed to prevent colds. In this section, two sample problems illustrate how to conduct a hypothesis test for the difference between two proportions.
