Tracking Signal $=$ Cumulative Error$/$MAD

Cumulative

$|$Absolute$|$ Absolute

Actual Cumulative $|$Forecast $|$ Forecast Tracking

Customers Forecast Error Error $|$Error $|$ Error MAD Signal

December $120130$

January $168170$

February $212200$

March $190180$

March MAD $=|$Actual $$ Forecast Errors$|=??????$

N

March Tracking Signal $=$ Cumulative Error

MAD $=??????$