
218 Chapter 5 rough SetS and BayeS’ theorieS
determine whether ice cream consumption depends on the variables
price, income, or temperature. The variables Lag-temp and Year have been
added to the original data. The table contains the following attributes:
Date• : Time period (1–30) of the study (from 3/18/51 to 7/11/53)
IC• : Ice cream consumption in pints per capita
Price• : Price of ice cream per pint in dollars
Income• : Weekly family income in dollars
Temp• : Mean temperature in degrees F
Lag-temp• : Temp variable lagged by one time period
Year• : Year within the study (0 = 1951, 1 = 1952, 2 = 1953)
Follow the rough-set approach ...