The script „run_analysis.R“ must be run in the same directory as the extracted „UCI HAR Dataset“, which can be downloaded here: http://archive.ics.uci.edu/ml/machine-learning-databases/00240/UCI%20HAR%20Dataset.zip
For more information about the „UCI HAR Dataset“, please see here: http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones
The script „run_analysis.R“ performs the following analysis on the data in the directory „UCI HAR Dataset“:
- It first reads the data on participants, activities observed and various measurements from the files in the test and train directories into separate variables.
- It then reads the different descriptive names for the activities in the activity variable from the file ‚activity_labels.txt’ as well as the variable names for the different measurements from the file ‚features.txt‘. It labels the different measurements with the names from ‚features.txt‘.
- After that, it extracts only the measurements on the mean and standard deviation for each measurement. It then combines the subject and the activity variables with these extracted variables into a single data frame, containing the test as well as the trainin data.
- It then replaces the number coding of the activity variable with the descriptive values from ‚activity_labels.txt‘ and also labels the different measurements with more descriptive variable names.
- Finally, it creates an independent tidy data set with the average of each variable for each activity and each subject.
- It then writes this data set to a file called „tidy_data.txt“ in the same directory as „run_analysis.R“.