HLTH 501 WEEK 3 PROBLEMS30 POINTS 10 points per problem. Put answers in the table: 1. 2. 3. 1. A clinical trial is conducted comparing a new pain medication for arthritis. Participants are randomly assigned to receive the new medication or a placebo. The outcome is pain relief within 30 minutes. The data are shown below. New Medication Placebo Pain Relief 44 A 21 C No Pain Relief 76 B 99 D Estimate the risk difference in pain relief between treatments = a/a+b - c/c+d= .191 Estimate the relative risk in pain relief between treatments = RR= a/(a+b)/c/(c+d)= . 7677 or 2.09 Estimate the odds ratio in pain relief between treatments = a/b / c/d=a x d/b x c= . 0027=2.729 The upper and lower limits of the are shown below Lower Limit of CI: ____0.41____ Upper Limit of CI: ___1.61_____ Based on the Confidence Interval values which of the following are true? Page 1 of 3 HLTH 501 A. One can be 95% confident that the true value will be greater than the upper limit. B. One can be 95% confident that the true value will be greater than the lower limit. C. One can be 95% confident that the true value will between the upper and lower limit. D. a and b + 2. The following data were collected in a clinical trial evaluating a new compound designed to improve wound healing in trauma patients. The new compound is compared against a placebo. After treatment for 5 days with the new compound or placebo the extent of wound healing is measured and the data are shown below. Treatment New Compound (n=125) Placebo (n=125) 0-25% 15 36 Percent Wound Healing 26-50% 51-75% 37 32 45 34 76-100% 41 10 Is there a difference in the extent of wound healing by treatment? (Hint: Are treatment and the percent wound healing independent?) Run the appropriate test at a 5% level of significance. df= n-1= 125-1=124________ alpha= _0.05_______ 2 Reject H0 if > ________ Compute expected frequencies Expected Frequency = (Row Total * Column Total)/N. Complete the expected frequencies for each cell. Treatment New Compound Placebo Total Compute 0-25% 15 ( ) 36 ( ) 51 Percent Wound Healing 26-50% 51-75% 37 32 ( ) ( ) 45 34 ( ) ( ) 82 66 Total 76-100% 41 ( ) 10 ( ) 51 125 125 250 2 . 2= ________ 2 2 Based on comparing the computed to the rejection level which of the following is (are) true? A. We have statistically significant evidence at alpha=0.05 to show that H0 is false. B. Treatment and percent wound healing are not independent. Page 2 of 3 HLTH 501 C. Treatment and percent wound healing are independent. D. a and b. 3. A clinical trial is conducted comparing a new pain reliever for arthritis to a placebo. Participants are randomly assigned to receive the new treatment or a placebo and the outcome is pain relief within 30 minutes. The data are shown below. New Medication Placebo Pain Relief 44 21 No Pain Relief 76 99 Is there a significant difference in the proportions of patients reporting pain relief? Run the test at a 5% level of significance. Reject H0 if Z < ________ or if Z > ________ alpha= ________ = = ________ ________ = ________ Z = ________ Based on comparing the computed z to the rejection level z which of the following is (are) true? A. We have statistically significant evidence at alpha=0.05 to show that H0 is false. B. We have statistically significant evidence at alpha=0.05 to show that there a significant difference in the proportions of patients reporting pain relief. C. We do not have statistically significant evidence at alpha=0.05 to show there a significant difference in the proportions of patients reporting pain relief. D. a and b Page 3 of 3