Solution Found!
Solved: Effectiveness of Diet. Listed below are weights
Chapter 10, Problem 5 CRE(choose chapter or problem)
Problem 5 CRE
Effectiveness of Diet. Listed below are weights (lb) of subjects before and after the Zone diet. (Data are based on results from “Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction, “ by Dansingeret al, Journal of the American Medical Association, Vol. 293, No. 1.) Use the data for Exercises.
Before |
183 |
212 |
177 |
209 |
155 |
162 |
167 |
170 |
After |
179 |
198 |
180 |
208 |
159 |
155 |
164 |
166 |
Diet Clinical Trial: Correlation Use the before/after weights listed above.
a. Test for a correlation between the before and after weights.
b. If each subject were to weigh exactly the same after the diet as before, what would be the value of the linear correlation coefficient?
c. If all subjects were to lose 5% of their weight from the diet, what would be the value of the linear correlation coefficient found from the before/after weights?
d. What do the preceding results suggest about the suitability of correlation as a tool for testing the effectiveness of the diet?
Questions & Answers
QUESTION:
Problem 5 CRE
Effectiveness of Diet. Listed below are weights (lb) of subjects before and after the Zone diet. (Data are based on results from “Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction, “ by Dansingeret al, Journal of the American Medical Association, Vol. 293, No. 1.) Use the data for Exercises.
Before |
183 |
212 |
177 |
209 |
155 |
162 |
167 |
170 |
After |
179 |
198 |
180 |
208 |
159 |
155 |
164 |
166 |
Diet Clinical Trial: Correlation Use the before/after weights listed above.
a. Test for a correlation between the before and after weights.
b. If each subject were to weigh exactly the same after the diet as before, what would be the value of the linear correlation coefficient?
c. If all subjects were to lose 5% of their weight from the diet, what would be the value of the linear correlation coefficient found from the before/after weights?
d. What do the preceding results suggest about the suitability of correlation as a tool for testing the effectiveness of the diet?
ANSWER:
Solution 5 CRE
a)
The value of correlation coefficient is 0.9647. The critical value of the correlation coefficient is .the value of correlation coefficient is not within the critical value range and is beyond the right tail range of the critical value hence the variables are linearly correlated .the value of p is 0.000 which is statistically highly significant and less than the value of level of significance of 0.05 to support the claim that the weights of the subjects before and after the zone diet are linearly correlated.
b)
If the subjects exactly weights the same before and after the zone diet then the value of correlation will be equal to 1. Which is seen from the following output assuming before and after values are the same. The data can be analyzed and the result of correlation and regression can be obtained through STAT DISK as follows: