Vacation destinations often run on a seasonal basis, depending on the primary activities in that location. Amanda Wang is the owner of a travel agency in Cincinnati, Ohio. She has built a database of the number of vacation packages (Vacation) that she has sold over the last twelve years. The accompanying table contains a portion of quarterly data on the number of vacation packages sold.


Year Quarter Vacation
2008 1 540
2008 2 187
⋮ ⋮ ⋮
2019 4 963

Year Quarter Vacation
2008 1 540
2008 2 187
2008 3 1354
2008 4 713
2009 1 1024
2009 2 624
2009 3 1489
2009 4 1165
2010 1 249
2010 2 498
2010 3 1397
2010 4 584
2011 1 523
2011 2 320
2011 3 1432
2011 4 820
2012 1 380
2012 2 1043
2012 3 1732
2012 4 823
2013 1 821
2013 2 449
2013 3 1697
2013 4 832
2014 1 711
2014 2 809
2014 3 1108
2014 4 560
2015 1 656
2015 2 815
2015 3 1255
2015 4 554
2016 1 272
2016 2 532
2016 3 1621
2016 4 1068
2017 1 591
2017 2 909
2017 3 1154
2017 4 516
2018 1 445
2018 2 452
2018 3 1161
2018 4 594
2019 1 706
2019 2 769
2019 3 1323
2019 4 963

Estimate the linear regression models using seasonal dummy variables with and without the trend term. Which is the preferred model? (Negative values for regression coefficients should be indicated by a minus sign. Round your answers to 2 decimal places.)

Use the preferred model to forecast the quarterly number of vacation packages sold in the first two quarters of 2020. (Round coefficient estimates to at least 4 decimal places and final answers to 2 decimal places.)