Four features were extracted from each of the the 3 axes of the accelerometer, giving a total of 12 attributes. The features extracted were:
• Mean
      the arithmetic mean, also called the mathematical expectation or average, is the central value of a         discrete set of numbers
• Standard Deviation
         is a measure that is used to quantify the amount of variation or dispersion of a set of data values
• Energy
        
• Correlation.