The run_analysis.R script prepares a tidy data set with the following steps:
- combine feature measurements from the train and test data set
- combine subjects from the train and test data set
- select mean and std measurements
- set the column names of the selected features
- include subjects as the first column
- include activity label as the last column
- calculate mean of each feature column group by subject and activity
- output result to avg_by_subject_activity.txt