Retail gas, part 2.

In Exercise 30 we looked at the weekly average retail price (cents per gallon) of regular gas nationwide from 2002 through the early part of 2007.

Here’s a time series plot:

d) Comment on any patterns you see.

Transcribed Image Text:

Price 301 251 201 151 wwwww + + 2002 2003 2004 2005 2006 2007 Year a) What components can you see in this plot? Here's a linear trend model fit to these data. Dependent variable is: Price R squared 82.3% s-21.88 with 282 Variable Coeff - R squared (adjusted) 82.2% 2 280 degrees of freedom Intercept Year SE (Coeff) t-ratio P-value -60025.3 30.0388 1668 -36.0 0.0001 0.8322 36.1 0.0001 b) Interpret the trend coefficient in this model. c) How would you interpret the intercept coefficient? Here's a time series plot of the residuals. I mm Wy + 2002 2003 2004 2005 2006 2007 Year