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, 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: Carpeted rooms: x=184 s= 22.0
Uncarpeted rooms: x=175 s=16.9

The P-value for this test is greater than 0.25. Which of the following is a reasonable conclusion?

a. There are outliers in these data, so we can't rely on the two-sample t test.
b. This test is unreliable because the populations we're sampling from are heavily skewed.
c. There isn't much evidence to support a conclusion that the presence of carpet is associated with an increase or decrease in the mean bacterial concentration of air.
d. There is fairly strong evidence to support a conclusion that the presence of carpet is associated with an increase or decrease in the mean bacterial concentration of air.