title	author	date	output
README.Rmd	Simon Filiatrault	Monday, August 18, 2014	html_document

Getting and Cleaning Data

This README explains the content of the project files for the getting and cleaning data coursera course project. The goal of this project is to:

Goal of this project

create one R script called run_analysis.R that does the following.

1. Merges the training and the test sets to create one data set.
2. Extracts only the measurements on the mean and standard deviation for each measurement.
3. Uses descriptive activity names to name the activities in the data set
4. Appropriately labels the data set with descriptive variable names.
5. Creates a second, independent tidy data set with the average of each variable for each activity and each subject.

Files descriptions

Files	Description	Details
run_analysis.R	This file is the main analysis script	It will do the 5 steps above
CodeBook.Rmd	This is the CookBook explaining the project	Listing all steps in "cooking" the data in details
README.Rmd	This file	Explains the files and data input / output
README.html	This file in HTML format	In case you want to see a nice output
CodeBook.html	The cookbook in HTML	Easier to read
X_Merge_Data_Averages_Grouped.txt	The merged data set	Created in step 5 above

Data set descriptions

NOTE: For the details of how the DATA was "Cooked", please open the CookBook.html

The original dataset is seperated in many files with not very descriptive column names. The main data set has over 500 columns, so this project goal is to extract part of this dataset Another goal is to add the activity and users (two seperated dataset) in the main one When this is done, we can merge the two main data set, the training one and the test one. See the CookBook.html for details.

Variables

The column names have been "renamed" to have more descriptive names.
The approch I took is to replace terms like "t" with more descriptive name "Time" for example The downside of having a more descriptive name is that the column name can become long So you can choose what to search&replace to suite your needs and taste. Finding the balance that work for you. Again, details are in the CookBook.html

How to run the analysis

First you need to download the zip datasets and extract in your working directory. This will create this structure:

• UCI HAR Dataset
  • test
    • Inertial Signals
  • train
    • Inertial Signals

The datasets we need are located under the test and train subfolder. The scripts in run_analysis.R is coded for this.

Enjoy!