Question

The air in poultryr processing plant 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 colonyforming units (CFUs) are counted after an incubation pen'od. Here are the data cm two locations in a plant that process 37,000 turkeys per day, taken on tourl days in the summer. The units are CFUS per cubic meter of air. Location Day 1 Day 2 Day 3 Day 4 Kill Room 3 183 2 540 I 731 1 070 Processing 594 111 325 298 Researchers would like to estimate m the average difference between the CFle in the Kill Room versus the CFUs in the Processing room. Calculate the point estimate for the true average dierence [Kill Room - Processing} Rotmd to two decimal pieces. Set up the 95% condence interval for the true average difference [Kill Room - Processing Room}. The standard deviation of differences is sd = 862. Find the appropriate critical value and calculate the standard error. Recall. all condence intervals share the same general form: Estimate :l: Critical Value x Standard Error Add a direction to the interpretation of the condence interval. This emphasizes which group was larger and which was smaller. The 95% Condence Interval estimates the processing room CFUs. on average. 427 to 3171 |:| "' than the kill room CFUs. A, Less B More