5547. x̅=25.9, n=144, σ=3. The standard deviation σ=3 of a normally distributed random variable X, the sample mean x̅v=25.9, and the sample size n=144 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)