English or languish - Probing the ramifications
of Hong Kong's language policy

Regression Analysis
project index | statistical modelling (prognostics) | factor analysis (decision tree)

 Goodness of fit Linearity - Examination of error terms with respect to each independent variable Plot error terms against each independent variable. Partitioning the error terms Requires multiple observations of the dependent variable for each value of the independent variables F - statistic Comparing explained with unexplained error. Constant variance of the error term - Plot error terms against predicted values of the dependent variable. Independence of error terms - Plot error terms against time. Normality of error term distribution. Construct a histogram of error terms Plot the cumulative standardized residuals against a straight line. Addition of other variables - Regress error terms against additional variable. Statistical significance T - tests against the null hypothesis for individual independent variables. F - test (Coefficient of determination) - the ratio of explained variation and unexplained variation Predictive value Only predict within the range of the sample estimated Strength of association - regression coefficients Beta coefficients - Coefficients resulting from standardized data that permit direct comparison of the relative importance of each independent variable on the dependent variable. Beta values provide useful comparisons only when multicollinearity is small the number and kind of variables remain the same the range of values of each variable do not change. Selecting the best predictive model - Stepwise regression analysis Backward elimination - a process of elimination whereby a small number of independent variables are chosen from among many independent variables with varying degrees of predictive power. Stepwise forward estimation - a process by which additional independent variables are added to the regression equation based on their ability to account for the unexplained error left by other independent variables Dummy variables top