StatisticsdrillTwo-proportion z test
A statistics problem from Statisticsdrill. Solve it with one answer box, with a fresh sample on every attempt and the worked steps and spreadsheet function in the answer, and it is checked the moment you submit.
The task
Two branches piloted a cross-sell offer. Branch A: 46 of 200 customers accepted. Branch B: 84 of 600 accepted. Test H0: pA = pB against H1: pA ≠ pB. Find the z statistic (A minus B, pooled standard error), then decide at α = 0.01. Round to 2 decimal places.
What this problem teaches
Under H0 the proportions are equal, so pool them: p = (x1 + x2) / (n1 + n2). SE = √(p(1 - p)(1/n1 + 1/n2)).
A hint if you get stuck
Under H0 the proportions are equal, so pool them: p = (x1 + x2) / (n1 + n2). SE = √(p(1 - p)(1/n1 + 1/n2)).
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