19) What is the “reverse causality” problem in determining cause and effect?
A) It is a problem that occurs when one concludes that a change in variable X caused a change in
variable Y when in actual fact, it is a change in variable Z that caused a change in variable Y.
B) It is a problem that occurs when one observes that a change in variable X caused a change in variable
Y which caused a change in variable Z and concludes that a change in variable X caused a change in
variable Z.
C) It is a problem that occurs when one concludes that a change in variable X caused a change in
variable Y when in actual fact, it is a change in variable Y that caused a change in variable X.
D) It is a problem that arises when two variables are inter-connected so that a change in variable X
causes a change in variable Y, and a change in variable Y causes a change in variable X.
20) The number of people who have gray hair is very high among residents living in Florida. A student
concludes that living in Florida causes hair to turn gray. What is the flaw in this student’s reasoning?
A) The student is drawing a false conclusion by making the mistake of omitting critical variables such
as the age and gender of the residents.
B) The student is using an inadequate sample size.
C) The student is drawing a false conclusion; he is confusing cause and effect.
D) The student has failed to take into account other causes of gray hair.
21) You explain to your friend Haslina, who runs a catering service called “Meals in a Zip,” about an
economic theory which asserts that consumers will purchase less of a product at higher prices than they
will at lower prices. She contends that the theory is incorrect because over the past two years she has
raised the price of her catered meals and yet has seen a brisk increase in sales. How would you respond
to Haslina?
A) Haslina is right; she has evidence to back her claim. The theory must be erroneous.
B) I will explain to her that she is making the error of reverse causality: it is the increase in demand that
has enabled her to raise her prices.
C) I will explain to her that there are some omitted variables that have contributed to an increase in her
sales such as changes in income.
D) Haslina is making the mistake of assuming that correlation implies causation.