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.
Conduct a matched pairs t-test to see if the differences in locations is significant. (note: Conduct the test so the mean difference will be positive.)
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Day 1
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Day 2
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Day 3
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Day 4
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Kill room
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3175
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2526
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1763
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1090
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Processing
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529
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141
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362
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224
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1. The value of the mean difference is (round your answer to one decimal place).
2. The standard error of the difference is (round your answer to two decimal places)
3. The degrees of freedom for this test are
4. The value of the test statistic is (round your answer to two decimal places)
5. Using an applet like this one you can find on the internet, CrunchIt, software, or your calculator, provide the exact p-value for the hypothesis test. Round your answer to three decimal places.
6. At alpha=0.05 the null hypothesis is rejected.
True or False
7. At alpha = 0.01 the null hypothesis is rejected.
True or False
8. At alpha = 0.10 the null hypothesis is rejected.
True or False
9. In the answer boxes below fill in the (1) lower bound and (2) upper bound of the 95% Confidence Interval for the difference. Round your answer to two decimal places.
Answer 1
Answer 2
10. We can tell just by looking at the confidence interval that Ho was rejected at the 0.05 level without having to conduct the t-test.
True or False