Problem N5625 probability theory confidence interval

Problem N5625 probability theory confidence interval

5625. A survey of 10,000 train passengers was carried out, as a result of which the average travel distance of passengers was found to be 24.2 km. Determine with a reliability of 0.6827 the possible limits of the mathematical expectation of the travel distance of passengers, assuming the distribution of the travel distance of passengers is normal with a standard deviation of 12 km

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