Course Notes - Department of Mathematics and Statistics

Source of variation SS DF MS FRegression(x) 1306.0 1Regression(d| x) (700.3) (1) 700.3 13.6Regression(d,x) 2006.3 2Residual (Error) 669.4 13 51.5Total 2675.7 35Extra sum of squares model• This F statistic is strongly significant, suggesting the introductionof d is important in the model.R -Squared• Adding d raised the R-Sq value from 48.8% to 75%.• This shows a definite improvement in the model once d is included.Age adjusted• Without taking age into account the treatment was felt to onlyincrease blood pressure by 6.25 mm of mercury only.• Taking age into account, the treatment raised blood pressure by14.082.• There were more older people in the treatment group, which whenage isn’t taken into account could confound the results.10.8 Logistic Regression• So far we have looked at continuous outcome variables, what dowe do if the outcome variable is binary?1. Disease present yes/no2. Tuatara: present/absent3. Claim to ACC goes to litigation: yes/no• We use logistic regression.253