A major bank collected data on 100,000 of its customers (income, sex, location, number of cards, etc.) and then computed how much profit it made from the account of these customers during 2010.
(a) Identity whether the data are cross sectional or a time series.
(b) Give a name to each variable and indicate it the variable is categorical, ordinal, or numerical (it a variable is numerical, include its units it possible).
(c) List any concerns that you might have tor the accuracy of the data.