5413. x̅=18.61, n=81, σ=6. Given the standard deviation σ=6 of a normally distributed random variable X, sample mean x̅=18.61, sample size n=81. Find confidence intervals for estimating the unknown mathematical expectation a with a given reliability γ=0.95.

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