Retail prices of food items. In 1990, the average weekly food cost for a suburban family of four was estimated to be $154.40. The table (next column) presents the retail prices of four food items for selected years from 1990 to 2015. Assume a typical suburban family of four purchased the following quantities of food, on average, each week during 1990: Spaghetti Ground Beef Eggs Potatoes 2 lb. 5 lb. 1 doz. 10 lb Spaghetti ($/lb.) Ground Beef ($/lb.) Eggs ($/doz.) Potatoes ($/lb.) 1990 .85 1.63 1.00 .32 1995 .88 1.40 1.16 .38 2000 .88 1.63 .96 .35 2005 .87 2.30 1.35 .50 2010 1.19 2.38 1.79 .58 2015 1.34 4.23 2.06 .65 Source: US Census Bureau.

a. Calculate a Laspeyres price index for 1990 to 2015, using 1990 as the base year.

b. According to your index, how much did the above “basket” of foods increase or decrease in price from 1990 to 2015?