Course Project - Getting and Cleaning Data Author

Instructions

Clone this repository and run the run_analysis.R script from within the cloned repository root directory.

This script will download and process the data set generating a tidy data set at ./data/TidyDataSet.txt

Data Source

This project uses the "Human Activity Recognition Using Smartphones Dataset" downloaded to ./data/Dataset.zip by run_analysis.R from: https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

Script Walkthrough

The run_analysis.R script will perform the following steps:

Require reshape2 library (for the melt() function) Ensure the data path exists (./data) Checks if the data set archive was already downloaded Downloading the data set archive if it was not already Timestamps the data set archive file with when it wad downloaded Extracts the data set files from the archive Reads training & test column files into respective x,y,s variables Reads feaure names and sets column/variable names respectively Appends the training and test data set rows Creates a unified data set (data frame) Extracts measurements on mean & standard deviation, for each measurement Sets activity names on the class labels Labels data with descriptive variable/column names by removing special characters in the column names and by replacing hyphen's with underscores in the column names Removes columns used only for tidying up the data set (intermediate calculations) Melts the data set (note this is why we require reshape2 library) Creates a second, independent, tidy data set which contains the average of each variable for each activity and subject Saves the resulting tidy data set to file ./data/TidyDataSet.txt