The file P02_55.xlsx contains monthly sales (in millions of dollars) of beer, wine, and liquor. The data have not been seasonally adjusted, so there might be seasonal patterns that can be discovered.
a. Create a new Month Name variable with values Jan, Feb, and so on. (Use Excel’s MONTH function and then a lookup table.)
b. Create side-by-side box plots of Total Sales, broken down by Month Name. Is there any evidence of differences across months for either the level of sales or the variability of sales?