The average length of time customers spent on waiting at ABC Store's check-out counter before a new P.O.S. system was installed was 5.3 minutes. A sample of 49 customers randomly selected at the check-out counter after the new P.O.S. system was installed showed that the average waiting time was 5.8 minutes with a sample standard deviation of 2.3 minutes. We wish to determine if there has been a signicant increase (from 5.3 minutes) in the average waiting time after the P.O.S. system was installed. Take α = 0.05. Construct a 95% confidence interval for the average waiting time after the new P.O.S. system was installed.

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