From Test method, select the method for estimating the proportion. When the samples are large and equal, the default method of estimating the proportions separately is preferred. If the samples are equal but small the default method is less accurate.
When you select Use the pooled estimate of the proportion, the Hypothesized difference must be equal to 0 and Minitab does not calculate a confidence interval based on the pooled estimate of the proportion. Minitab still displays a confidence interval, but it is calculated based on the default method of estimating the proportions separately.