This R script run_analysis.R does the following:
- Downloads and unzips the dataset if not already existing.
- Loads activity and feature files.
- Loads training and test data sets and selects only mean and standard deviation measurements.
- Includes subject and activity data for both training and test datasets.
- Merges the training and the test sets to create one data set.
- Updates activity labels.
- Creates a second, independent tidy data set with the average of each variable for each activity and each subject.