Question: A randomized trial is conducted to evaluate the effectiveness of a newly developed treatment for joint pain in arthritis patients. The treatment is compared to an established treatment that has been shown to be effective. Two hundred patients with arthritis agree to participate and are randomly assigned to either the newly developed treatment or to the established treatment. Among the several clinical outcomes in the investigation, we focus on a secondary outcome, quality of life. The following data were observed:

a) Conduct the appropriate hypothesis test, assuming normality, to determine whether the mean quality of life differs between the two groups. Use an alpha = 0.05.

b) Construct a 95% confidence interval for the difference in mean quality of life between the treatments.

c) Based on your answer to part B, is there a significant difference in mean quality of life scores between treatments? Justify your answer. Does the confidence interval calculated in part B confirm or contradict your conclusion in part A?