Problem $18-18($Algo$)$

A particular forecasting model was used to forecast a six$-$month period. Here are the forecasts and actual demands that resulted:

FORECAST ACTUAL

April $252202$

May $327256$

June $402322$

July $352302$

August $378334$

September $452409$

a$.$ Find the tracking signal for each month. $($Negative values should be indicated by a minus sign. Round your answers to the nearest whole number.$)$