Problem
To allow for the possibility that expenditure on your category is partly subject to a one-period lag, regress the logarithm of expenditure on your commodity on LGDPI, the logarithm of your relative price series, and those two variables lagged one period. Repeat the experiment adding LGDPI(-2) and the logarithm of the price series lagged two periods. Compare the regression results, paying attention to the changes in the regression coefficients and their standard errors.
The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.