Chapter 18, Problem 37CE

Consider the variable mean amount per transaction in the Home Depot data presented above. This variable indicates, for example, that the average customer spent $39.13 on goods during a store visit in 1993. By 2012 this amount increased to $54.89. During that same period the Consumer Price Index (CPI) as reported by the Bureau of Labor Statistics increased from 144.5 to 229.594. Convert the CPI to a 1993 base, as described on page 640 in the previous chapter, and convert the mean amount per transaction to 1993 dollars. Develop a linear trend equation for the constant 1993 dollars of the mean amount per transaction. Is it reasonable that the trend is linear? Can we conclude that the value of the amount the customer spent is less?