pashadow / gacd-courseproject

Getting and Cleaning Data, Course Project

Course Project - Getting and Cleaning Data

The experiments have been carried out with a group of 30 volunteers within an age bracket of 19-48 years. Each person performed six activities (WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, LAYING) wearing a smartphone (Samsung Galaxy S II) on the waist. Using its embedded accelerometer and gyroscope, we captured 3-axial linear acceleration and 3-axial angular velocity at a constant rate of 50Hz. The experiments have been video-recorded to label the data manually. The obtained dataset has been randomly partitioned into two sets, where 70% of the volunteers was selected for generating the training data and 30% the test data.

The run_analysis.R script tidies a set of data made available at https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip.

See also the full description of the experiment which created the set http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones.

• First make sure the HCI HAR Dataset directory is in the working directory.
• Then source run_analysis.R.

See the Code Book for more details.

Script run_analysis.R does following:

• Load data into R
• 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.
• Uses descriptive activity names to name the activities in the data set.
• Appropriately labels the data set with descriptive variable names.
• From the data set in step 4, creates a second, independent tidy data set with the average of each variable for each activity and each subject.

Result is stored in file "result.txt" in the current folder.