Over the past 5 years, the mean time for a warehouse to ?ll a buyers order has been 25 minutes. Offcials of the company believe that the length of time has increased recently, either due to a change in the workforce or due to a change in customer purchasing policies. The processing time (in minutes) was recorded for a random sample of 15 orders processed over the past month.
28 25 27 31 10
26 30 15 55 12
24 32 28 42 38
Do the data present suffcient evidence to indicate that the mean time to ?ll an order has increased at 5% signi?cance level? Use P-value approach.