The Consumer Price Index (CPI) measures the price change of a constant market basket of goods and services.The Bureau of Labor Statistics publishes a national CPI (called the US. City Average Index) as well as separate indexes for each of 32 different cities in the United States. The CPI is used in cost-of-living escalator clauses of many labor contracts to adjust wages for inflation (Bureau of Labor Statistics Handbook of Methods, 1992). The table below lists the published values of the U.S. City Average Index and the Chicago Index during 1994 and 1995.

a. Calculate the mean values for the U.S. City Average Index and the Chicago Index.

b. Find the ranges of the U.S. City Average Index and the Chicago Index.

c. Calculate the standard deviation for both the U.S.
City Average Index and the Chicago Index over the time period described in the table.

d. Which index displays greater variation about its mean over the time period in question? Justify your response.