In the long-run equilibrium in monopolistic competition, price equals marginal cost

Figure 17-10 Refer to . A result of the tariff is that, relative to the free-trade situation, the quantity of saddles imported decreases by

a. Q₂ - Q₁.
b. Q₃ - Q₂.
c. Q₄ - Q₃.
d. Q₄ - Q₃ + Q₂ - Q₁.

What is the "omitted variable" problem in determining cause and effect?

A) It is a problem that arises when an insignificant variable is given too much weight in an economic analysis leading to skewed conclusions about cause and effect. B) It is a problem that arises when a significant variable is not given enough weight in an economic experiment leading to skewed conclusions about cause and effect. C) It is a problem that arises when an insignificant economic variable that should have been omitted is included in an economic experiment leading to false conclusions about cause and effect. D) It is a problem that arises when an economic variable that affects other variables is omitted from an analysis and its omission leads to false conclusions about cause and effect.