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StatisticsHardConfidence Intervals

Confidence Intervals · Hard problem

A company claims its light bulbs last 100100 days on average. A random sample of 3636 bulbs has xˉ=103.2\bar x = 103.2 days and s=9s = 9 days. Using t∗=2.030t^* = 2.030 (3535 degrees of freedom), is 100100 a plausible value for the mean at 95%95\% confidence?