The (simulated) data (mg decrease per decilitre of blood) forthe Omega-3 group is stored in Table A1, and the data for thecontrol group is stored in Table A2. You are required to calculatea 95% confidence interval for the average difference in cholesterolreduction and to test the hypothesis that there was no differencebetween the two diets in average reduction of cholesterol.

1. How many patients were in each dietgroup?

2. What was the mean (decrease) in cholesterol for theOmega-3 group of patients?

3. What was the standard deviation in that group?LABORATORY ASSIGNMENTS INTRODUCTORY STATISTICS LABORATORY37

4. What was the mean (decrease) in cholesterol for thecontrol group of patients?

5. What was the standard deviation in the controlgroup?

6. What is the estimated difference ofmeans?

7. Standard error of the difference between means 2 2 21 2 1 n s n s = + What is the standard error of the difference ofmeans?

b) Calculate the margin of error of the estimateddifference of means. For this large-sample 95% confidence intervalwe can approximate with a z value which is z0.025 = 1.96. Calculatethe confidence interval as difference between means ± margin oferror.

8. What is the margin of error of the estimateddifference?

9. What is the lower limit for the 95% confidenceinterval of the difference in cholesterol reduction between Omega-3and control diets?

10. What is the upper limit?

DATA A1:

86.6
73.9
99.4
67.9
82.3
80.3
82.8
77.9
76.8
85.9
62.5
34
120.9
57
114.9
83.7
103.5
67.4
86.1
87.6
104.2
123
91.7
95.2
95.8
90.7
72.9
72.9
62
98.1
70
77.3
34.8
58
66.7
100.6
98.6
75
52.9
54
42.1
86.7
68.9
68.8
76
87.1
99.2
119.3
88.5
90.9 DATA A2 52.5 38.6 60.7 90.8 57.9 38.6 31.9 35.2 27.7 31.5 39.4 80.4 61.1 88.1 37.5 43.5 35.6 81.6 55.2 66.7 56.3 47.4 105.2 51.7 35.8 58.9 24.5 92.8 55 52.5 110.2 86.5 30.7 50.8 58.2 75.1 73.9 12.5 23.3 96.6 55.6 102.9 103 50.2 88.7 53.7 41.5 24.7 80.3 84.4