Answer:
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.
Step-by-step explanation:
A. There are outliers in these data, so we can't rely on the two-sample t test.
There are no outliers, as the seven rooms for both sample have similar size and function.
B. This test is unreliable because the populations we're sampling from are heavily skewed.
We don't know if the populations are heavily skewed, but this effect should be appeased by the sampling.
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.
Correct conclusion, as the P-value is surely greater than the significance level (usually 0.10 at most).
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.
There is no evidence as the P-value is greater than the significance level.
