: value of z such that the area to its right is equal to. Confidence interval estimator of with known (+ or -, so it"s 2 tail : . Wilson estimator t-test of : t-estimator of : . Estimate the mean to within w units: . Confidence interval estimator of using the wilson estimator. : the area in the lower tail or upper tail of the sampling distribution of the sample mean. Confidence interval estimator of the total of a large finite population. Type i error: reject a true null hypothesis; probability: (significant level) Type ii error: not reject a false null hypothesis. Confidence interval estimator of the total number of success in a large finite population. If less than rejection region, cannot reject the null hypothesis in favor of the alternative. When is known, to test a population mean.