A hotel wanted to develop a new system for delivering room service breakfasts. In the current system, an order form is left on the bed in each room. If the customer wishes to receive a room service breakfast, he or she places the order form on the doorknob before 11 p.m. The current system requires customers to select a 15-minute interval for desired delivery time (6:30-6:45 a.m., 6:45-7:00 a.m., etc.). The new system is designed to allow the customer to request a specific delivery time. The hotel wants to measure the difference (in minutes) between the actual delivery time and the requested delivery time of room service orders for breakfast. (A negative time means that the order was delivered before the requested time. A positive time means that the order was delivered after the requested time.) The factors included were the menu choice (American or Continental) and the desired time period in which the order was to be delivered (Early Time Period [6:30-8:00 a.m.] or Late Time Period [8:00-9:30 a.m.]). Ten orders for each combination of menu choice and desired time period were studied on a particular day. The data are as follows:

Desired Time Type of Breakfast Early Time Period| Late Time Period Continental 1.2 -2.5 Continental 2.1 3.0 Continental 3.3 -0.2 Continental 4.4 1.2 Continental 3.4 1.2 Continental 5.3 0.7 Continental 2.2 -1.3 Continental 1.0 0.2 Continental 5.4 -0.5\f