avgs.txt contains six rows of data that has the mean of 79 variables (listed below) grouped by six activities (also listed below).
Here's how the data is manipulated to create a tidy data set in order to generate the means:
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Data dictionaries features.txt and activity_lables.txt are loaded into memory and given colNames ("id","measure") & ("id","activity")
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The test and training complete data sets (x_test.txt & x_train.txt) are both brought into memory
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Variables for these two datasets are set from the data dictionary for features (step 1) and then filtered to only include variables that are means or standard deviations
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The indexes of the filtered variables is used to reduce each data sets 79 independent variables and then the column names are renamed to the variable names from step 2
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The activites for each data set (y_test.txt & y_train.txt) is brought into memory, given a colname of "id" and then cbind to each data set
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The "id" variable in each data set is joined to the activity data dictionary from step 1. This gives each observation an easily recognized activity. This activity column is moved to the front of the column list and then the "id" column is removed to remove any confusion
AT THIS POINT THE DATA IS TIDY. EACH INDEPENDENT TRIAL HAS IT'S OWN ROW, WITH 79 INDEPENDENT VARIABLES DESCRIBING EACH OBSERVATION. THE VARIABLE NAMES AS WELL AS ACTIVITIES ARE EASILY READ.
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The two datasets are combined with rbind
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The mean of each column is taken after the complete data set is grouped by "activity" and is then written to the avgs.txt file.
activity chr Describes the activity undertaken when measurement taken VALUES: WALKING, WALKING_UPSTAIRS, WALKING_DOWNSTAIRS, SITTING, STANDING, LAYING
tBodyAcc-mean()-X num mean of Body Acc on the X axis
tBodyAcc-mean()-Y num mean of Body Acc on the Y axis
tBodyAcc-mean()-Z num mean of Body Acc on the Z axis
tBodyAcc-std()-X num std dev of Body Acc on the X axis
tBodyAcc-std()-Y num std dev of Body Acc on the Y axis
tBodyAcc-std()-Z num std dev of Body Acc on the Z axis
tGravityAcc-mean()-X num mean of Gravity Acc on the X axis
tGravityAcc-mean()-Y num mean of Gravity Acc on the Y axis
tGravityAcc-mean()-Z num mean of Gravity Acc on the Z axis
tGravityAcc-std()-X num std dev of Gravity Acc on the X axis
tGravityAcc-std()-Y num std dev of Gravity Acc on the Y axis
tGravityAcc-std()-Z num std dev of Gravity Acc on the Z axis
tBodyAccJerk-mean()-X num mean of Body Acc Jerk on the X axis
tBodyAccJerk-mean()-Y num mean of Body Acc Jerk on the Y axis
tBodyAccJerk-mean()-Z num mean of Body Acc Jerk on the Z axis
tBodyAccJerk-std()-X num std dev of Body Acc Jerk on the X axis
tBodyAccJerk-std()-Y num std dev of Body Acc Jerk on the Y axis
tBodyAccJerk-std()-Z num std dev of Body Acc Jerk on the Z axis
tBodyGyro-mean()-X num mean of Body Gyro on the X axis
tBodyGyro-mean()-Y num mean of Body Gyro on the Y axis
tBodyGyro-mean()-Z num mean of Body Gyro on the Z axis
tBodyGyro-std()-X num std dev of Body Gyro on the X axis
tBodyGyro-std()-Y num std dev of Body Gyro on the Y axis
tBodyGyro-std()-Z num std dev of Body Gyro on the Z axis
tBodyGyroJerk-mean()-X num mean of Body Gyro Jerk on the X axis
tBodyGyroJerk-mean()-Y num mean of Body Gyro Jerk on the Y axis
tBodyGyroJerk-mean()-Z num mean of Body Gyro Jerk on the Z axis
tBodyGyroJerk-std()-X num std dev of Body Gyro Jerk on the X axis
tBodyGyroJerk-std()-Y num std dev of Body Gyro Jerk on the Y axis
tBodyGyroJerk-std()-Z num std dev of Body Gyro Jerk on the Z axis
tBodyAccMag-mean() num mean of Body Acc Mag
tBodyAccMag-std() num std dev of Body Acc Mag
tGravityAccMag-mean() num mean of Gravity Acc Mag
tGravityAccMag-std() num std dev of Gravity Acc Mag
tBodyAccJerkMag-mean() num mean of Body Acc Jerk Mag
tBodyAccJerkMag-std() num std dev of Body Acc Jerk Mag
tBodyGyroMag-mean() num mean of Body Gyro Mag
tBodyGyroMag-std() num std dev of Body Gyro Mag
tBodyGyroJerkMag-mean() num mean of Body Gyro Jerk Mag
tBodyGyroJerkMag-std() num std dev of Body Gyro Jerk Mag
fBodyAcc-mean()-X num mean of Fast Fourier Transform of Body Acc on the X axis
fBodyAcc-mean()-Y num mean of Fast Fourier Transform of Body Acc on the Y axis
fBodyAcc-mean()-Z num mean of Fast Fourier Transform of Body Acc on the Z axis
fBodyAcc-std()-X num std dev of Fast Fourier Transform of Body Acc on the X axis
fBodyAcc-std()-Y num std dev of Fast Fourier Transform of Body Acc on the Y axis
fBodyAcc-std()-Z num std dev of Fast Fourier Transform of Body Acc on the Z axis
fBodyAcc-meanFreq()-X num mean frequency of Fast Fourier Transform of Body Acc on the X axis
fBodyAcc-meanFreq()-Y num mean frequency of Fast Fourier Transform of Body Acc on the Y axis
fBodyAcc-meanFreq()-Z num mean frequency of Fast Fourier Transform of Body Acc on the Z axis
fBodyAccJerk-mean()-X num mean of Fast Fourier Transform of Body Acc Jerk on the X axis
fBodyAccJerk-mean()-Y num mean of Fast Fourier Transform of Body Acc Jerk on the Y axis
fBodyAccJerk-mean()-Z num mean of Fast Fourier Transform of Body Acc Jerk on the Z axis
fBodyAccJerk-std()-X num std dev of Fast Fourier Transform of Body Acc Jerk on the X axis
fBodyAccJerk-std()-Y num std dev of Fast Fourier Transform of Body Acc Jerk on the Y axis
fBodyAccJerk-std()-Z num std dev of Fast Fourier Transform of Body Acc Jerk on the Z axis
fBodyAccJerk-meanFreq()-X num mean frequency of Fast Fourier Transform of Body Acc Jerk on the X axis
fBodyAccJerk-meanFreq()-Y num mean frequency of Fast Fourier Transform of Body Acc Jerk on the Y axis
fBodyAccJerk-meanFreq()-Z num mean frequency of Fast Fourier Transform of Body Acc Jerk on the Z axis
fBodyGyro-mean()-X num mean of Fast Fourier Transform of Body Gyro on the X axis
fBodyGyro-mean()-Y num mean of Fast Fourier Transform of Body Gyro on the Y axis
fBodyGyro-mean()-Z num mean of Fast Fourier Transform of Body Gyro on the Z axis
fBodyGyro-std()-X num std dev of Fast Fourier Transform of Body Gyro on the X axis
fBodyGyro-std()-Y num std dev of Fast Fourier Transform of Body Gyro on the X axis
fBodyGyro-std()-Z num std dev of Fast Fourier Transform of Body Gyro on the X axis
fBodyGyro-meanFreq()-X num mean frequency of Fast Fourier Transform of Body Gyro on the X axis
fBodyGyro-meanFreq()-Y num mean frequency of Fast Fourier Transform of Body Gyro on the Y axis
fBodyGyro-meanFreq()-Z num mean frequency of Fast Fourier Transform of Body Gyro on the Z axis
fBodyAccMag-mean() num mean of Fast Fourier Transform of Body Acc Mag
fBodyAccMag-std() num std dev of Fast Fourier Transform of Body Acc Mag
fBodyAccMag-meanFreq() num mean frequency of Fast Fourier Transform of Body Acc Mag
fBodyBodyAccJerkMag-mean() num mean of Fast Fourier Transform of Body Acc Jerk Mag
fBodyBodyAccJerkMag-std() num std dev of Fast Fourier Transform of Body Acc Jerk Mag
fBodyBodyAccJerkMag-meanFreq() num mean frequency of Fast Fourier Transform of Body Acc Jerk Mag
fBodyBodyGyroMag-mean() num mean of Fast Fourier Transform of Body Gyro Mag
fBodyBodyGyroMag-std() num std dev of Fast Fourier Transform of Body Gyro Mag
fBodyBodyGyroMag-meanFreq() num mean frequency of Fast Fourier Transform of Body Gyro Mag
fBodyBodyGyroJerkMag-mean() num mean of Fast Fourier Transform of Body Gyro Jerk Mag
fBodyBodyGyroJerkMag-std() num std dev of Fast Fourier Transform of Body Gyro Jerk Mag
fBodyBodyGyroJerkMag-meanFreq() num mean frequency of Fast Fourier Transform of Body Gyro Jerk Mag