Question

Complete entire problem, showing ALL work so the learner can transpose into a notebook.

3. (SECTION 11.2) Spam e-mail has become a serious and costly nuisance. An office manager believes that the average amount of time spent by office workers reading and deleting sparn is NOT 25 minutes per day. To test this beliel, he takes a random sample of 18 workers and measures the amount of time each spends reading and deleting spam. The results are listed here. If the population of times is normal with a standard deviation of 12 minutes, can the manager infer at the 2% significance level that he is correct? 3548 294 17 21 32 28 34 23 13 9 11 30 42 37 93

Answer 1

ANSWER Given data M=25 0212 n=18 Mean of the sample is a = - 29.6667 Test hypothesis age Well hypothesis Ho: ju=25 Alternative hypothesis Ho:14 15 Test statistic jä-pu Test statistic Za — olun 29.6667-25 - 121578 5165 Pvalue P-value = 2P(Z 1.65) = 00990 becasion Since P-value = 0.02 hence fail to reject the null hypothesis Conclusion There is not sufficient evidence to conclude that the average amount of time spent by office woske om 1. deleting spam is not 25 min/day