Задача N5620 теория вероятностей доверительный интервал

5620. A sample from a large batch of electric lamps contains 100 lamps. The average burn time of the sampled lamps was found to be 900 hours. Find an approximate 0.94 confidence interval for the average lamp life of the entire lot if the standard deviation of the lamp burn time of the lot is known to be 41 hours.

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