Over the past 5 years, the mean time for a warehouse to fill a buyer’s order has been 25...

Over the past 5 years, the mean time for a warehouse to fill a buyer’s order has been 25 minutes. Officials 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.

Do the data present sufficient evidence to indicate that the mean time to fill an order has increased?