Problem N5612 probability theory confidence interval

Problem N5612 probability theory confidence interval

5612. From a large batch of light bulbs, a sample of 10 bulbs was made for testing for burning duration. The average duration of burning turned out to be equal to mx=3000 hours. Assuming that the duration of burning the bulb has a normal distribution with a standard deviation σh=35 hours, find the confidence interval for m=M(x) with reliability γ=0.95

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