Geting and Cleanning Human Activity Recognition Using Smartphones Data Set

Introduction:

The goal is to prepare tidy data that can be used for later analysis.

The data source will be: https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

And its explanation could be found: http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones

Transformation done by run_analysis.R:

Load Data Set

Load the X_train.txt and X_test.txt datasets and bind them together into 1 main dataset

Select only Mean and Std columns

The meassurements that were representatives for this analysis were all the Means and StdDev. Using regular expressions the script selects only the columns containing that data and creates a subset of the original one.

Labels the data set

As the original labels were too hard to read, using regular expresions the script changes the original names for more readable ones using as input the features.txt file. Also, adds to the beggining the words MeanOf, so the final script can contains more representative names.

Using descriptives activities names

The script pulls out all the activities from the y_train.txt and y_test.txt. After that it changes the numbers by more understandable names and attach it to the data set in the first position

Add Subjects and create a tidy data set

After that, the scripts adds the subject column from subjects_train.txt and subjects_test.txt. Using the dplyr package to calculate the average of each variable for each activity and each subject. Finally, the script exports the tidy data to a txt file using write.table.