The code basically works in the following steps
- Merges the training and the test sets to create one data set.
- Extracts only the measurements on the mean and standard deviation for each measurement.
- Assigns descriptive activity names to name the activities in the data set
- Appropriately labels the data set with descriptive variable names.
- Creates a second, independent tidydata set with the average of each variable for each activity and each subject.
- Finally, writes the data in a text file as instructed in the assignment.