https://pinboard.in/u:rahuldave/public/ recent bookmarks from rahuldave 2012-03-01T14:00:00+00:00 http://www.r-bloggers.com/r-tutorial-series-centering-variables-and-generating-z-scores-with-the-scale-function/ rahuldave #center variable A using the scale() function> scale(A, center = TRUE, scale = FALSE)You can verify these results by making the calculation by hand, as demonstrated in the following screenshot. Centering a variable with the scale() function and by hand Generating Z-ScoresNormally, to create z-scores (standardized scores) from a variable, you would subtract the mean of all data points from each individual data point, then divide those points by the standard deviation of all points. Again, this can be accomplished in one call using scale(). > #generate z-scores for variable A using the scale() function> scale(A, center = TRUE, scale = TRUE)Again, the following screenshot demonstrates equivalence between the function results and hand calculation. Generating z-scores from a variable by hand and using the scale() function Complete Scale() ExampleTo see a complete example of how scale() can be used to center variables and generate z-scores in R, please download the scale() example (.txt) file. ReferencesThe official scale function manual page is available from: http://stat.ethz.ch/R-manual/R-patched/library/base/html/scale.html To leave a comment for the author, please follow the link and comment on his blog: R Tutorial Series. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series,ecdf, trading) and more... ]]> R_bloggers centering R_Tutorial_Series r-project scale standardized_scores tutorial Variables z-scores https://pinboard.in/u:rahuldave/b:b1aa1aef81cd/ 2012-02-02T18:07:10+00:00 http://code.google.com/edu/languages/google-python-class/introduction.html rahuldavegoogle python programming tutorial https://pinboard.in/ https://pinboard.in/u:rahuldave/b:073050eb4a0a/ 2010-04-21T17:45:00+00:00 http://feeds.arstechnica.com/~r/arstechnica/index/~3/tGM5tqWsxfY/tutorial-use-twitters-new-real-time-stream-api-in-python.ars rahuldave Features Guides Open-source Web programming python tutorial twitter https://pinboard.in/u:rahuldave/b:58ebd66b4b7c/