StatisticsdrillSampling distribution of the mean
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
Order values at an online shop have mean $197 and standard deviation $2. A random sample of 16 orders is taken. What is the probability that the sample mean is above $196.10? Round to 4 decimal places.
What this problem teaches
With n of 30 or more the sample mean is close to normal even when single orders are skewed.
A hint if you get stuck
The sample mean has standard error σ / √n. Use that, not σ, in the z-score.
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