A z-test to compare two population proportions is to be conducted. One condition for this z-test to be valid is that both samples sizes are large.

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For a z-test comparing two population proportions to be valid, both sample sizes need to be large enough to ensure that the sampling distribution of the difference between proportions is approximately normal. This is often assessed using the rule of thumb that both $np_1(1-p_1)$ and $np_2(1-p_2)$ should be greater than 10, where $n$ is the sample size and $p$ is the proportion for each group.

A Z-Test to Compare Two Population Proportions Is to Be