7. Researchers wanted to determine if carpeted bathrooms contained more bacteria

than uncarpeted bathrooms. Researchers pumped air from randomly chosen

bathrooms over a Petri dish. Colonies of bacteria were allowed to form in the 16 Petri

dishes. The results are presented in the table. Assume the data is approximately

normal and independent. Do carpeted bathrooms have more bacteria than

uncarpeted bathrooms at the a = 0.05 level of significance? (the units are

bacteria/cubic foot)

11.8

8.2

Carpeted Bathrooms

10.8

10.1

7.1

13.0

14.6

14.0

12.1

8.3

Uncarpeted Bathrooms

3.8

7.2

12.0

11.1

10.1

13.7