An Economics Professor Is Taping 60-Minute Lectures for Replay Over

Short Answer

An economics professor is taping 60-minute lectures for replay over the university radio station.To make sure that the brand of tapes that will be used records for at least sixty minutes,one dozen are purchased and examined to determine if they do record for sixty minutes.The results of the recording test in minutes show a mean of 61.28 and standard deviation of 3.868.The professor assumes that the playing time is normally distributed.Construct an 80-percent confidence interval for the mean recording time employing these data.
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