Is yearly income a continuous variable or a discrete variable?

Answer 1

Actually, it can be and is frequently treated as either. If the data is collected as a numerical value (for example, $35,500), then it is continuous. However, it is often simpler and more useful, especially in surveys, to collect the data as a set of ranges (20,000 - 29,999; 30,000 - 39,999; etc.). In this case, it would be an ordinal variable. Ordinal variables are discreet categories that still have a rank order.