1. WSUG May 2012 Tools Review – SPSS Sam Ledgar Yorkshire Water Services

2. Graphs – a selection

5. Graphing the raw data

7. Regression analysis

14. Suggested further analysis Normality test applied to standardised residuals Examination of outliers with respect to ‘x’ (leverage) and ‘y’ (dffits and dfbetas) Cook’s distance Possible transformation of the data and repeating regression

17. Results of further analyses Standardised residuals appear to be normally distributed (p>0.05) Leverage – points of influence Jan 10, Dec 10 Dffits – points of influence Jan 10, Feb 10 & Dec 10 Dfbetas – intercept – Sept 09, Jan 10, Jun 10 - parameter – Dec 08, Jan 10-, Feb 10 & Dec 10 Cook’s Distance – Jan 10 Possible concerns re: Jan 10 & Dec 10???

18. Scatterplot of Cook’s Distance vs Leverage

20. Software positives Drop down menus! Graphboard Template Chooser Comprehensive worked examples available Syntax behind drop down selections is given in output – ease of repeat commands Relatively quick and easy to use Curve Estimation for single regressor variables

21. Software negatives Modular – additional modules required for advanced modelling techniques, time series etc Relatively expensive Syntax commands not simple Slow to upgrade UAT possible not the best (?) – patch upgrades Occasional problems with importing date variables Prefer look of Excel graphs Limited distributions available for PHM