Use this information for all questions on this page.Is there a difference in the amount of airborne bacteria between carpeted and uncarpeted rooms? In an experiment, 7 rooms were carpeted and 7 were left uncarpeted. The rooms are similar in size and function. After a suitable period of time, the concentration of bacteria in the air was measured (in units of bacteria per cubic foot) in all of these rooms. The data and summaries are provided:

	Sample mean	Sample standard deviation
Carpeted rooms:	184	22.0
Uncarpeted rooms:	175	16.9

Use Minitab Express to calculate a 95% confidence interval for the difference in mean bacterial concentration in the air of carpeted rooms versus uncarpeted rooms.

Select one:

a.-7.47 to 31.47.

b.-11.55 to 29.55.

c.-14.08 to 32.08.

d.-18.89 to 42.89.