Spam e-mail has become a serious and costlynuisance. An office manager believes that the average amount of time spent by office workers reading and deleting spam exceeds25minutesper day. To testthisbelief,hetakesarandomsampleof 18 workersandmeasurestheamountoftime eachspendsreadinganddeletingspam. Theresultsarelisted here. If the population of times is normal witha standard deviation of 12 minutes, can the manager infer at the 1% significance level that he is correct? Use the p-value approach. (Hint: whenever we know the population standard deviation, we should use it instead of the sample standard deviation.)

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