The file P03_15.xlsx contains monthly data on the various components of the Consumer Price Index. a. create differences for each of the variables. You can do this quickly with StatTools, using the Difference item in the Data Utilities dropdown list, or you can create the differences with Excel formulas. b. Create a times series graph for each CPI component, including the All Items component. Then create a time series graph for each difference variable. Comment on any patterns or trends you see. c. Create a table of correlations between the differences. Comment on any large correlations (or the lack of them). d. Create a scatterplot for each difference variable versus the difference for All Items (Y axis). Comment on any patterns or outliers you see.