A clinical trial isrun to evaluate the efficacy of a new medication to relieve pain inpatients undergoing total knee replacement surgery. In the trial,patients are randomly assigned to receive either the new medicationor the standard medication. After receiving the assignedmedication, patients are asked to report their pain on a scale of0-100 with higher scores indicative of more pain. Data on theprimary outcome are shown below.
| Sample Size | Mean Pain Score | Standard Deviation ofPain Score |
New Medication | 60 | 30.31 | 7.52 |
StandardMedication | 60 | 53.85 | 7.44 |
Because procedures canbe more complicated in older patients, the investigators areconcerned about confounding by age. For analysis, patients areclassified into two age groups, less than 65 and 65 years of ageand older. The data are shown below.
Age < 65 Years | Sample Size | Mean Pain Score | Standard Deviation ofPain Score |
New Medication | 40 | 25.30 | 2.46 |
StandardMedication | 25 | 45.51 | 1.83 |
Total: Age < 65Years | 65 | 33.07 | 10.16 |
| | | |
Age 65+ Years | Sample Size | Mean Pain Score | Standard Deviation ofPain Score |
New Medication | 20 | 40.33 | 2.16 |
StandardMedication | 35 | 59.80 | 2.49 |
Total: Age 65+ | 55 | 52.72 | 9.74 |
- Is there a statistically significant difference in mean painscores between patients assigned to the new medication as comparedto the standard medication? Run the appropriate test at ï¡=0.05.(Ignore age in this analysis.)
