Problem N5430 probability theory confidence interval

Problem N5430 probability theory confidence interval

5430. x̅=3.4, n=49, σ=1. The random variable X has a normal distribution with a known standard deviation σ=1. Find the confidence intervals for estimating the unknown mathematical expectation a from the sample means x̅=3.4 if the sample size is n=49 and the reliability of the estimate is γ=0.9.

Additional information:

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