A number of restaurants feature a device that allows credit card users to swipe their cards at the table. It allows the user to specify a percentage or a dollar amount to leave as a tip. In an experiment to see how it works, a random sample of credit card users was drawn. Some paid the usual way, and some used the new device. The percent left as a tip was recorded and listed below. Usinga= 0.05, what can we infer regarding users of the device?

Usual:

12.4, 14.2, 11.7, 11.4, 11.9, 11.4, 10.6,12.1, 14.2, 15.9, 13.9

Device:

12.0, 15.2, 9.9, 12.2, 14.9, 13.4, 12.1, 13.0, 10.3, 13.2

a.There is statistically significant evidence to conclude that users of the device leave larger tips than customers who pay in the usual manner.

b.There is statistically significant evidence to conclude that users of the device leave smaller tips than customers who pay in the usual manner.

c.There is statistically significant evidence to conclude that users of the device and customers who pay in the usual manner do not differ in the percentage value of their tips.

d.There is insufficient statistical evidence to make any conclusions from this data.