"The air in poultry-processing plants often contains fungus spores. Inadequate ventilation can affect the health of the workers. The problem is most serious during the summer. To measure the presence of spores, air samples are pumped to an agar plate and "colony forming units (CFUs)" are counted after an incubation period. Here are data from two locations in a plant that processes 37,000 turkeys per day, taken on four days in the summer. The units are CFUs per cubic meter of air.
Day 1 Day 2 Day 3 Day 4
Kill room 3175 2526 1763 1090
Processing 529 141 362 224
Data set
1. Explain carefully why these are matched pairs data.
A. These are matched pairs data because the sample is too small for other procedures.
B. These are matched pairs data because any research about fungus in the air must be designed as a matched pairs study.
C. These are matched pairs data because every day one measurement was taken from each group.
D. These are matched pairs data because there are exactly two groups - Kill room and Processing.
2. The spore count is clearly higher in the kill room. Give a 99% confidence interval to estimate how much higher.
A. 1407.46 to 2241.55
B. −611.46 to 4260.46
C. −3047.42 to 6696.42
D. −95.58 to 3744.58
3. You will often see the t procedures used for data like these. You should regard the results as only rough approximations. Why?
A. It is due to the large value of s.
B. It is due to the large value of x.
C. It is due to the small value of n.
D. It is due to the small value of t.