Android :: Inconsistency On Definition Of Sign Of X Acceleration?

I'm just wondering...on Android Web, I could find two completely opposite ways of defining which direction the positive X acceleration is. http://developer.android.com/reference/android/hardware/SensorEvent.html At the bottom, it says "When the device lies flat on a table and is pushed on its left side toward the right, the x acceleration value is positive. " However, http://developer.android.com/reference/android/hardware/SensorListene..., it says "When the device is pushed on its left side toward the right, the x acceleration value is negative (the device applies a reaction force to the push toward the left) "