The article "Capillary Leak Syndrome in Children With C4A-Deficiency Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Double-Blind, Randomised Controlled Study" (S. Zhang, S. Wang, et al., Lancet, 2005:556-562) presents the results of a study of the effectiveness of giving blood plasma containing complement component C4A to pediatric cardiopulmonary bypass patients. Of 58 patients receiving C4A-rich plasma, the average length of hospital stay was 8.5 days and the standard deviation was 1.9 days. Of 58 patients receiving C4A-free plasma, the average length of hospital stay was 11.9 days and the standard deviation was 3.6 days. Can you conclude that the mean hospital stay is shorter for patients receiving C4A-rich plasma?