CodeBook.md

Getting and Cleaning Data

Course Project Code Book

Input files and required information

Source data can be found at: https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip

Description of the data is at http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones

Project description

The run_analysis.R script cleans up the data by:

• merging the training and test sets to create one data set, namely train/X_train.txt with test/X_test.txt, train/subject_train.txt with test/subject_test.txt, and train/y_train.txt with test/y_test.txt.

• reading features.txt and extracting only the measurements on the mean and standard deviation for each measurement.

• reading activity_labels.txt and appliying descriptive activity names to name the activities in the data set:

  • walking
  • walkingupstairs
  • walkingdownstairs
  • sitting
  • standing
  • laying

• labelling the data set with descriptive names. All attributes are converted to lower case, underscores and brackets () are removed.The names of the attributes are similar to the following:

  • tbodyacc-mean-x
  • tbodyacc-mean-y
  • tbodyacc-mean-z
  • tbodyacc-std-x
  • tbodyacc-std-y
  • tbodyacc-std-z
  • tgravityacc-mean-x
  • tgravityacc-mean-y

• creating a 2nd tidy data set clean_data_with_average.txt with the average of each measurement for each activity and each subject.