Suppose the demand for pens increases and the supply for pens ...

[crobinson2013]

Suppose the demand for pens increases and the supply for pens decreases. What effect will it have on the quantity?
 a. It will rise
  b. It will fall
  c. uncertain
  d. None

Question 2

The presence of association between two variables does not necessarily imply causation for the following reason(s):
 a. the association between two variables may result simply from pure chance
  b. the association between two variables may be the result of the influence of a third common factor
  c. both variables may be the cause and the effect at the same time
  d. a and b
  e. a, b, and c

[macagnavarro]

Answer to Question 1

c

Answer to Question 2

e