Задача N5426 теория вероятностей доверительный интервал

5426. x̅=75.14, n=81, σ=9. Find the confidence interval for estimating the mathematical expectation a of a normal distribution with a reliability of 0.95, knowing the sample mean x̅=75.14, the sample size n=81, and the standard deviation σ=9.

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)