codebook.txt

Data Dictionary
Human Activities summary analysis 
for Coursera Getting and Cleaning Data project (May 2015 session).

Observations
Each row is labeled with the identifier of the test subject and the activity engaged in (and the word "means" describing the analysis). Example:

  Subject_1_WALKING_NORMAL_means     

Activities
Subjects were observed while engaged in 6 target activities. Those were:

1 WALKING (WALKING_NORMAL)
2 WALKING_UPSTAIRS
3 WALKING_DOWNSTAIRS
4 SITTING
5 STANDING
6 LAYING

NOTE: In order to make programming less error prone, for this analysis the activity "WALKING" was changed to "WALKING NORMAL"

Features

The features of the dataset are a subset of those from the original data. Original data variables are described in terms of how they were measured (gyroscope or accelerometer) and the axis of measurement (X, Y or Z). In addition, some summary statistics of these variables were generated. In the current analysis, only those variables including mean or standard deviation were used and a mean calculated for each. This leads to the following column names:


MEAN_OF_tBodyAcc-mean()-X 
MEAN_OF_tBodyAcc-mean()-Y 
MEAN_OF_tBodyAcc-mean()-Z 
MEAN_OF_tBodyAcc-std()-X 
MEAN_OF_tBodyAcc-std()-Y 
MEAN_OF_tBodyAcc-std()-Z 
MEAN_OF_tGravityAcc-mean()-X 
MEAN_OF_tGravityAcc-mean()-Y 
MEAN_OF_tGravityAcc-mean()-Z 
MEAN_OF_tGravityAcc-std()-X 
MEAN_OF_tGravityAcc-std()-Y 
MEAN_OF_tGravityAcc-std()-Z 
MEAN_OF_tBodyAccJerk-mean()-X 
MEAN_OF_tBodyAccJerk-mean()-Y 
MEAN_OF_tBodyAccJerk-mean()-Z 
MEAN_OF_tBodyAccJerk-std()-X 
MEAN_OF_tBodyAccJerk-std()-Y 
MEAN_OF_tBodyAccJerk-std()-Z 
MEAN_OF_tBodyGyro-mean()-X 
MEAN_OF_tBodyGyro-mean()-Y 
MEAN_OF_tBodyGyro-mean()-Z 
MEAN_OF_tBodyGyro-std()-X 
MEAN_OF_tBodyGyro-std()-Y 
MEAN_OF_tBodyGyro-std()-Z 
MEAN_OF_tBodyGyroJerk-mean()-X 
MEAN_OF_tBodyGyroJerk-mean()-Y 
MEAN_OF_tBodyGyroJerk-mean()-Z 
MEAN_OF_tBodyGyroJerk-std()-X 
MEAN_OF_tBodyGyroJerk-std()-Y 
MEAN_OF_tBodyGyroJerk-std()-Z 
MEAN_OF_tBodyAccMag-mean() 
MEAN_OF_tBodyAccMag-std() 
MEAN_OF_tGravityAccMag-mean() 
MEAN_OF_tGravityAccMag-std() 
MEAN_OF_tBodyAccJerkMag-mean() 
MEAN_OF_tBodyAccJerkMag-std() 
MEAN_OF_tBodyGyroMag-mean() 
MEAN_OF_tBodyGyroMag-std() 
MEAN_OF_tBodyGyroJerkMag-mean() 
MEAN_OF_tBodyGyroJerkMag-std() 
MEAN_OF_fBodyAcc-mean()-X 
MEAN_OF_fBodyAcc-mean()-Y 
MEAN_OF_fBodyAcc-mean()-Z 
MEAN_OF_fBodyAcc-std()-X 
MEAN_OF_fBodyAcc-std()-Y 
MEAN_OF_fBodyAcc-std()-Z 
MEAN_OF_fBodyAcc-meanFreq()-X 
MEAN_OF_fBodyAcc-meanFreq()-Y 
MEAN_OF_fBodyAcc-meanFreq()-Z 
MEAN_OF_fBodyAccJerk-mean()-X 
MEAN_OF_fBodyAccJerk-mean()-Y 
MEAN_OF_fBodyAccJerk-mean()-Z 
MEAN_OF_fBodyAccJerk-std()-X 
MEAN_OF_fBodyAccJerk-std()-Y 
MEAN_OF_fBodyAccJerk-std()-Z 
MEAN_OF_fBodyAccJerk-meanFreq()-X 
MEAN_OF_fBodyAccJerk-meanFreq()-Y 
MEAN_OF_fBodyAccJerk-meanFreq()-Z 
MEAN_OF_fBodyGyro-mean()-X 
MEAN_OF_fBodyGyro-mean()-Y 
MEAN_OF_fBodyGyro-mean()-Z 
MEAN_OF_fBodyGyro-std()-X 
MEAN_OF_fBodyGyro-std()-Y 
MEAN_OF_fBodyGyro-std()-Z 
MEAN_OF_fBodyGyro-meanFreq()-X 
MEAN_OF_fBodyGyro-meanFreq()-Y 
MEAN_OF_fBodyGyro-meanFreq()-Z 
MEAN_OF_fBodyAccMag-mean() 
MEAN_OF_fBodyAccMag-std() 
MEAN_OF_fBodyAccMag-meanFreq() 
MEAN_OF_fBodyBodyAccJerkMag-mean() 
MEAN_OF_fBodyBodyAccJerkMag-std() 
MEAN_OF_fBodyBodyAccJerkMag-meanFreq() 
MEAN_OF_fBodyBodyGyroMag-mean() 
MEAN_OF_fBodyBodyGyroMag-std() 
MEAN_OF_fBodyBodyGyroMag-meanFreq() 
MEAN_OF_fBodyBodyGyroJerkMag-mean() 
MEAN_OF_fBodyBodyGyroJerkMag-std() 
MEAN_OF_fBodyBodyGyroJerkMag-meanFreq() 
MEAN_OF_angle(tBodyAccMean,gravity) 
MEAN_OF_angle(tBodyAccJerkMean),gravityMean) 
MEAN_OF_angle(tBodyGyroMean,gravityMean) 
MEAN_OF_angle(tBodyGyroJerkMean,gravityMean) 
MEAN_OF_angle(X,gravityMean) 
MEAN_OF_angle(Y,gravityMean) 
MEAN_OF_angle(Z,gravityMean)

For more information about the variables and their meanings please see the file features_info.txt in the root of the zipfile at https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip. For a complete list of feature names see features.txt within the same archive.

Values in each column are floating point numbers between -1 and 1.