Table gives the retail sales (in billions of 1996 dollars) of the United States from the first quarter of 1995 to the fourth quarter of 1999. (a) Prepare a table showing sales, a time trend, and dummy variables to take into account seasonal effects. (b) Using the data from the table in part a, run a regression of sales on inventories and the seasonal dummies and interpret the results.
Table Retail Sales in the United States (in Billions of 1996 $)
|
Sales quarter year
|
540.5
|
608.5
|
606.6
|
648.3
|
568.4
|
632.8
|
626.0
|
674.6
|
587.0
|
640.2
|
|
I
|
II
|
III
|
IV
|
I
|
II
|
III
|
IV
|
I
|
II
|
|
1995
|
1996
|
1997
|
|
Sales quarter year
|
645.9
|
686.9
|
597.0
|
675.3
|
663.6
|
723.3
|
639.5
|
716.5
|
721.9
|
779.9
|
|
III
|
IV
|
I
|
II
|
III
|
IV
|
I
|
II
|
III
|
IV
|
|
1997
|
1998
|
1999
|