Mean (SD), cohort 1: control 45.88 (7.29), drug 50.86 (2.01)
Mean (SD), both cohorts: control 46.48 (6.41), drug 51.50 (4.87)
Planned analysis, cohort 1 only: n = 8 per group, difference 4.98 s, t = 1.86, p = 0.0836
After adding cohort 2 (unplanned): n = 12 per group, difference 5.03 s, t = 2.16, p = 0.0418
Welch's t-test instead: cohort 1 p = 0.0992; both cohorts p = 0.0426
Both cohorts, cohort as a block: difference 5.03 s (95% CI 0.14 to 9.91), p = 0.0442
Cohort 2 alone: n = 4 per group, difference 5.12 s, p = 0.3413