5540. x̅=25.22, n=81, σ=6. The standard deviation σ=6 of a normally distributed random variable X, the sample mean x̅v=25.22, and the sample size n=81 are given. Find the confidence interval for estimating the unknown mathematical expectation a with a given confidence probability γ=0.95.

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