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, 2005:556562) 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?

Week 10 8 November 2016 Basic Statistics for Research Professor HK Dong Wendy Liu Population Margin of Error: Conservative margin of error: use Sample size needed to obtain certain margin of error: Statistical methods Descriptive statistics Inferential statistics o Estimation (confidence intervals) o Hypothesis testing Hypothesis testing – inferential procedure that uses sample data to evaluate the credibility of a hypothesis about the population H a alternative hypothesis Research hypothesis you wish to establish H 0 null hypothesis Nullifies the research hypothesis 1. State the hypothesis 2. Define the decision method 3. Gather data 4. Make a decision a. Reject the H 0