ERRORS IN THE FINAL QUANTITY Z=X+Y · Linear combination Z+dz=X+dx+Y+ dyl Error in Z is dz=dx+dy BUT this is worst case For random errors we could have dz=dx-dyl or dyl-dx These errors are much smaller In general if different errors are not correlated, are independent, the way to combine them is dz=dx+dy This is true for random and bias errors13 ERRORS IN THE FINAL QUANTITY • Z = X + Y • Linear combination – – Error in Z is BUT this is worst case • For random errors we could have – or – These errors are much smaller • In general if different errors are not correlated, are independent, the way to combine them is • This is true for random and bias errors Z + dz = X + dx + Y + dy dz = dx + dy dz = dx − dy dy − dx dz = dx 2 + dy 2