Created for Coursera course "Getting and Cleaning Data" Week 4 final project. From the data created in [1] Davide Anguita, Alessandro Ghio, Luca Oneto, Xavier Parra and Jorge L. Reyes-Ortiz. Human Activity Recognition on Smartphones using a Multiclass Hardware-Friendly Support Vector Machine. International Workshop of Ambient Assisted Living (IWAAL 2012). Vitoria-Gasteiz, Spain. Dec 2012 generates the mean of each mean and std for each of 17 variables, by subject and activity. The codebook for the variables of the matrix output by the script is feature_codebook.txt.