Question

A clinical trial is run to evaluate the efficacy of a new medication to relieve pain in patients undergoing total knee replacement surgery. In the trial, patients are randomly assigned to receive either the new medication or the standard medication. After receiving the assigned medication, patients are asked to report their pain on a scale of 0-100 with higher scores indicative of more pain. Data on the primary outcome are shown below. Sample Size Mean Pain Score Standard Deviation of Pain Score New Medication 50 31.13 7.25 Standard Medication 50 58.35 7.41 Because procedures can be more complicated in older patients, the investigators are concerned about confounding by age. For analysis, patients are classified into two age groups, less than 65 and 65 years of age and older. The data are shown below. Age < 65 Years Sample Size Mean Pain Score Standard Deviation of Pain Score New Medication 30 25.30 2.64 Standard Medication 27 45.51 1.38 Total: Age < 65 Years 57 33.07 10.61 Age 65+ Years Sample Size Mean Pain Score Standard Deviation of Pain Score New Medication 24 43.30 2.61 Standard Medication 31 58.90 2.94 Total: Age 65+ 55 57.22 9.47 Is there a statistically significant difference in mean pain scores between patients assigned to the new medication as compared to the standard medication? Run the appropriate test at alpha []=0.05. (Ignore age in this analysis.)

Answer 1