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Run Analysis Code Book

This codebook describe structure of data frame outputed by functions createTidyData and averageTidyData from run_analysis.R source.

###The data frame contains the following columns:

Identification

  • subject

    Number of the subject from which measurements of this row are made.

  • activity

    Activity the subject was performing during the measurements of the row.

Measure values

Accelerometer

  • tBodyAcc_mean_X, tBodyAcc_mean_Y, tBodyAcc_mean_Z

    Mean of the body part of accelerometer 3-axial signals

  • tBodyAcc_std_X, tBodyAcc_std_Y, tBodyAcc_std_Z

    Standard deviation of the body part of accelerometer 3-axial signals

  • tGravityAcc_mean_X, tGravityAcc_mean_Y, tGravityAcc_mean_Z

    Mean of the Gravity part of accelerometer 3-axial signals

  • tGravityAcc_std_X, tGravityAcc_std_Y, tGravityAcc_std_Z

    Standard deviation of the Gravity part of accelerometer 3-axial signals

Accelerometer Jerk (for body part)

  • tBodyAccJerk_mean_X, tBodyAccJerk_mean_Y, tBodyAccJerk_mean_Z

    Mean of the body part of accelerometer jerk 3-axial signals

  • tBodyAccJerk_std_X, tBodyAccJerk_std_Y, tBodyAccJerk_std_Z

    Standard deviation of the body part of accelerometer jerk 3-axial signals

Accelerometer Magnitude

  • tBodyAccMag_mean_X, tBodyAccMag_mean_Y, tBodyAccMag_mean_Z

    Mean of the magnitude of the body part of accelerometer 3-axial signals

  • tBodyAccMag_std_X, tBodyAccMag_std_Y, tBodyAccMag_std_Z

    Standard deviation of the magnitude of the body part of accelerometer 3-axial signals

  • tGravityAccMag_mean_X, tGravityAccMag_mean_Y, tGravityAccMag_mean_Z

    Mean of the magnitude of the Gravity part of accelerometer 3-axial signals

  • tGravityAccMag_std_X, tGravityAccMag_std_Y, tGravityAccMag_std_Z

    Standard deviation of the magnitude of the Gravity part of accelerometer 3-axial signals

Accelerometer Jerk Magnitude

  • tBodyAccJerkMag_mean_X, tBodyAccJerkMag_mean_Y, tBodyAccJerkMag_mean_Z

    Mean of the Magnitude of the body part of accelerometer jerk 3-axial signals

  • tBodyAccJerkMag_std_X, tBodyAccJerkMag_std_Y, tBodyAccJerkMag_std_Z

    Standard deviation of the magnitude of the body part of accelerometer jerk 3-axial signals

Gyroscope

  • tBodyGyro_mean_X, tBodyGyro_mean_Y, tBodyGyro_mean_Z

    Mean of the gyroscope 3-axial signals

  • tBodyGyro_std_X, tBodyGyro_std_Y, tBodyGyro_std_Z

    Standard deviation of the gyroscope 3-axial signals

Gyroscope Jerk

  • tBodyGyroJerk_mean_X, tBodyGyroJerk_mean_Y, tBodyGyroJerk_mean_Z

    Mean of the gyroscope jerk 3-axial signals

  • tBodyGyroJerk_std_X, tBodyGyroJerk_std_Y, tBodyAccJerk_std_Z

    Standard deviation of the gyroscope jerk 3-axial signals

Gyroscope Magnitude

  • tBodyGyroMag_mean_X, tBodyGyroMag_mean_Y, tBodyGyroMag_mean_Z

    Mean of the magnitude of the gyroscope 3-axial signals

  • tBodyGyroMag_std_X, tBodyGyroMag_std_Y, tBodyGyroMag_std_Z

    Standard deviation of the magnitude of the gyroscope 3-axial signals

Gyroscope Jerk Magnitude

  • tBodyGyroJerkMag_mean_X, tBodyGyroJerkMag_mean_Y, tBodyGyroJerkMag_mean_Z

    Mean of the magnitude of the gyroscope jerk 3-axial signals

  • tBodyGyroJerkMag_std_X, tBodyGyroJerkMag_std_Y, tBodyAccJerkMag_std_Z

    Standard deviation of the magnitude of the gyroscope jerk 3-axial signals

Measure values with Fast Fourier Transform (FFT)

Accelerometer

  • fBodyAcc_mean_X, fBodyAcc_mean_Y, fBodyAcc_mean_Z

    Mean of the body part of accelerometer 3-axial signals

  • fBodyAcc_std_X, fBodyAcc_std_Y, fBodyAcc_std_Z

    Standard deviation of the body part of accelerometer 3-axial signals

Accelerometer Jerk (for body part)

  • fBodyAccJerk_mean_X, fBodyAccJerk_mean_Y, fBodyAccJerk_mean_Z

    Mean of the body part of accelerometer jerk 3-axial signals

  • fBodyAccJerk_std_X, fBodyAccJerk_std_Y, fBodyAccJerk_std_Z

    Standard deviation of the body part of accelerometer jerk 3-axial signals

Accelerometer Magnitude

  • fBodyAccMag_mean_X, fBodyAccMag_mean_Y, fBodyAccMag_mean_Z

    Mean of the magnitude of the body part of accelerometer 3-axial signals

  • fBodyAccMag_std_X, fBodyAccMag_std_Y, fBodyAccMag_std_Z

    Standard deviation of the magnitude of the body part of accelerometer 3-axial signals

Accelerometer Jerk Magnitude

  • fBodyAccJerkMag_mean_X, fBodyAccJerkMag_mean_Y, fBodyAccJerkMag_mean_Z

    Mean of the Magnitude of the body part of accelerometer jerk 3-axial signals

  • fBodyAccJerkMag_std_X, fBodyAccJerkMag_std_Y, fBodyAccJerkMag_std_Z

    Standard deviation of the magnitude of the body part of accelerometer jerk 3-axial signals

Gyroscope

  • fBodyGyro_mean_X, fBodyGyro_mean_Y, fBodyGyro_mean_Z

    Mean of the gyroscope 3-axial signals

  • fBodyGyro_std_X, fBodyGyro_std_Y, fBodyGyro_std_Z

    Standard deviation of the gyroscope 3-axial signals

Gyroscope Magnitude

  • fBodyGyroMag_mean_X, fBodyGyroMag_mean_Y, fBodyGyroMag_mean_Z

    Mean of the magnitude of the gyroscope 3-axial signals

  • fBodyGyroMag_std_X, fBodyGyroMag_std_Y, fBodyGyroMag_std_Z

    Standard deviation of the magnitude of the gyroscope 3-axial signals

Gyroscope Jerk Magnitude

  • fBodyGyroJerkMag_mean_X, fBodyGyroJerkMag_mean_Y, fBodyGyroJerkMag_mean_Z

    Mean of the magnitude of the gyroscope jerk 3-axial signals

  • fBodyGyroJerkMag_std_X, fBodyGyroJerkMag_std_Y, fBodyAccJerkMag_std_Z

    Standard deviation of the magnitude of the gyroscope jerk 3-axial signals

Measurements Detail

From the original documentation:

The features selected for this database come from the accelerometer and gyroscope 3-axial raw signals tAcc-XYZ and tGyro-XYZ. These time domain signals (prefix 't' to denote time) were captured at a constant rate of 50 Hz. Then they were filtered using a median filter and a 3rd order low pass Butterworth filter with a corner frequency of 20 Hz to remove noise. Similarly, the acceleration signal was then separated into body and gravity acceleration signals (tBodyAcc-XYZ and tGravityAcc-XYZ) using another low pass Butterworth filter with a corner frequency of 0.3 Hz.

Subsequently, the body linear acceleration and angular velocity were derived in time to obtain Jerk signals (tBodyAccJerk-XYZ and tBodyGyroJerk-XYZ). Also the magnitude of these three-dimensional signals were calculated using the Euclidean norm (tBodyAccMag, tGravityAccMag, tBodyAccJerkMag, tBodyGyroMag, tBodyGyroJerkMag).

Finally a Fast Fourier Transform (FFT) was applied to some of these signals producing fBodyAcc-XYZ, fBodyAccJerk-XYZ, fBodyGyro-XYZ, fBodyAccJerkMag, fBodyGyroMag, fBodyGyroJerkMag. (Note the 'f' to indicate frequency domain signals).

To have more information, check the website at UCI