A combined estimate of the population proportion under the null hypothesis, calculated as p̂c = (n₁p̂₁ + n₂p̂₂)/(n₁ + n₂), used to check the normality condition for the sampling distribution of p̂₁ - p̂₂.
Topic 6.1: 6.10 Setting Up a Test for the Difference of Two Population Proportions
Unit 6