source this file to use the 'avgfeature' function
- tested with R version 3.5.1 (2018-07-02)
- dplyr
- dir_data: a directory where the UCI HAR Dataset have been extracted
- agg_file: a file name to save the output
- a dataset measurement aggregated over subjects and activities
- a .txt file described in the Codebook.md in your working directory