Used car dealerships generally have sales quotas that they strive to hit each month, quarter, and calendar year. Consequently, buying a used car toward the end of those periods presents a great opportunity to get a good deal on the car. The accompanying file includes monthly sales data for used cars $($Cars$)$ from $2014-2019.$

Estimate the linear regression models using seasonal dummy variables with and without the trend term. Which is the preferred model?

$\_\_\_\_\_\_$ based on the value of $\_\_\_\_\_\_\_.$

Use the preferred model to forecast used car sales in the first two months of $2020.$

Note: Round coefficient estimates to at least $4$ decimal places and final answers to $2$ decimal places.

Forecast

Month $1\_\_\_\_\_\_\_$

Month $2\_\_\_\_\_\_\_$

Date Cars

January$/14138$

February$/14179$

March$/14151$

April$/14176$

May$/14176$

June$/14212$

July$/14199$

August$/14233$

September$/14233$

October$/14202$

November$/14176$

December$/14180$

January$/15176$

February$/15148$

March$/15171$

April$/15166$

May$/15197$

June$/15199$

July$/15214$

August$/15230$

September$/15224$

October$/15177$

November$/15183$

December$/15173$

January$/16178$

February$/16133$

March$/16150$

April$/16168$

May$/16189$

June$/16210$

July$/16229$

August$/16234$

September$/16242$

October$/16168$

November$/16186$

December$/16191$

January$/17154$

February$/17142$

March$/17165$

April$/17173$

May$/17194$

June$/17203$

July$/17230$

August$/17206$

September$/17221$

October$/17167$

November$/17174$

December$/17183$

January$/18175$

February$/18152$

March$/18161$

April$/18170$

May$/18180$

June$/18184$

July$/18220$

August$/18220$

September$/18215$

October$/18172$

November$/18158$

December$/18170$

January$/19156$

February$/19150$

March$/19173$

April$/19184$

May$/19164$

June$/19201$

July$/19199$

August$/19206$

September$/19235$

October$/19146$

November$/19163$

December$/19195$