Wal-Mart revenue. Wal-Mart has grown rapidly in recent years. Here is the monthly revenue ($Billion) for Wal-

Mart from November 2003 to January 2007.

b) Interpret the coefficient of Time.

c) Interpret the coefficient of Dec.

d) What revenue would you predict for Wal-Mart in February 2007 (the 40th month in this series)?

e) What does it mean that the coefficient for Oct is the only negative coefficient in the model?

Transcribed Image Text:

25 Wal-Mart Revenue ($B) 8 15- 10 huhubert + Month Nov May Nov May Nov May Nov Year 2003 2004 2005 2006 a) What components of a time series do you see in this timeplot? Here's a regression model fit using dummy variables for months and a Time variable that counts from 1 for the first data value in the series. Dependent variable is: WM Rev R squared 94.3% R squared (adjusted) - 91.6% s-1.121 with 39 13 26 degrees of freedom Variable Coeff Intercept 12.0322 SE(Coeff) 0.6562 t-ratio P-value 18.3 <0.0001 Time 0.145241 0.0163 8.93 0.0001 Feb 1.46096 0.8599 1.70 0.1013 Mari 2.84671 0.8585 3.32 0.0027 Apr 1.67981 0.8574 1.96 0.0609 May 0.870232 0.8567 1.02 0.3191 Jun 4.99999 0.8562 5.84 0.0001 Jul 0.106417 0.8560 0.124. 0.9020 Aug 0.434176 0.8562 0.507 0.6164 Sep 3.25327 0.8567 3.80 0.0008 Oct -0.219640 0.8574 -0.256 0.7998 Nov 1.87023 0.7932 2.36 0.0262 Dec 11.5625 0.7927 14.6 0.0001