Statistics Two-Sample t Statistic

Question

Is there a difference in the amount of airborne bacteria between carpeted and uncarpeted rooms? In an experiment, seven rooms were carpeted and seven 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:

		s
Carpeted rooms:	184	22.0
Uncarpeted rooms:	175	16.9

The researcher wants to investigate whether the presence of carpet is associated with either an increase or decrease in the mean bacterial concentration in air. The numerical value of the two-sample t statistic for this test is

Answer 1