15. T F An independent variable is one whose value depends on the value of the dependent variable. 16. T F If the dependent variable changes in a direction like that of the independent variable, the relationship between the two is direct. 17. T F If an economy is operating on its production possibility curve, it must produce less of one good if it produces less of another. 18. T F The production-possibilities curve tells us which combination of goods a nation likes to produce. 19. T F An increase in income tends to cause an increase in quantity demanded of the consumers. 20. T F The law of diminishing marginal utility applies only to a given period