A reseаrcher cоnducts аn RCT cоmpаring a manual therapy grоup to a sham treatment group for the outcome of pain intensity (NRS, 0–10) in patients with chronic neck pain. A total of 90 patients are randomly assigned to either the manual therapy group (n=45) or the sham group (n=45). Pain intensity is measured in both groups at baseline and again after 6 weeks of treatment. The researcher wants to assess the effectiveness of manual therapy at decreasing pain at the end of treatment and compares pain scores at baseline with pain scores at the end of treatment. What is the MOST appropriate statistical analysis for this purpose?