In an attempt to decrease the average waiting time for customers to receive their drive-through orders, some participating starbucks locations in fresno, california have added a few touch screen stations for customers to place their orders directly from their vehicles. a random sample of 40 drive-through starbucks customers who place their order using this new touch screen feature is selected and the waiting time to receive their order is recorded. the resulting sample mean waiting time is 6.5 minutes and the standard deviation is 2.5 minutes. what distribution would you use to assess if the new touch screen drive-through ordering feature has significantly decreased the average waiting time to receive an order compared to the 7 minute average wating time reported for all drive-through starbucks customers in the us?