The mean waiting time at the​ drive-through of a​ fast-food restaurant from the time an order is placed to the time the order is received is 87.3 seconds. A manager devises a new​ drive-through system...

The mean waiting time at the​ drive-through of a​ fast-food restaurant from the time an order is placed to the time the order is received is

seconds. A manager devises a new​ drive-through system that

believes will decrease wait time. As a​ test,

initiates the new system at

restaurant and measures the wait time for

randomly selected orders. The wait times are provided in the table to the right. Complete parts​ (a) and​ (b) below.

103.3

81.3

69.8

95.4

59.9

85.9

73.8

72.2

67.1

81.3