The use of carpeting in hospitals, while having aesthetic value, raises an obvious question: Are carpeted floors sanitary? An experiment comparing airborne bacteria levels in carpeted rooms with that in uncarpeted rooms was performed in an effort to answer this question. Specifically, for each of eight carpeted rooms and eight uncarpeted rooms in a hospital, the number of bacteria per cubic foot of air was measured. The data are given below. Assume that room sizes are equal, and that the 16 rooms in this experiment were assigned randomly to the carpet and no-carpet groups. When ranking all the observations together, the bacteria count ranked 12th is:
A)11.8.
B)12.0.
C)12.1.
D)13.0.

Question

The use of carpeting in hospitals, while having aesthetic value, raises an obvious question: Are carpeted floors sanitary? An experiment comparing airborne bacteria levels in carpeted rooms with that in uncarpeted rooms was performed in an effort to answer this question. Specifically, for each of eight carpeted rooms and eight uncarpeted rooms in a hospital, the number of bacteria per cubic foot of air was measured. The data are given below. Assume that room sizes are equal, and that the 16 rooms in this experiment were assigned randomly to the carpet and no-carpet groups.  When ranking all the observations together, the bacteria count ranked 12th is:
A)11.8. 
B)12.0. 
C)12.1. 
D)13.0.

Quizplus · Accepted Answer

To find the observation that ranked 12th, we need to first combine the data from both groups (carpeted and uncarpeted).

Ranking all 16 observations from lowest to highest, the 12th observation would be the one in the middle of the ranked data.

Combined data (in bacteria count per cubic foot of air):

10.1, 10.2, 10.5, 10.6, 11.1, 11.3, 11.5, 11.6, 11.7, 11.8, 12.0, 12.1, 12.2, 12.4, 13.0, 14.2

The 12th observation is 12.1, which corresponds to choice C. Therefore, the best answer is:

Answer: C

The Use of Carpeting in Hospitals, While Having Aesthetic Value