This threat to external validity occurs when a pretest sensitizes ...

[mmm]

This threat to external validity occurs when a pretest sensitizes participants to the treatment yet
  to come.
 
  A) interaction of testing and treatment B) interaction of selection and treatment
  C) multiple-treatment interference D) reactive arrangements

Question 2

For each of the following designs, list the number of IVs and the number of levels for
  each specific IV:
  a. 2  2
  b. 2  4
  c. 3  2  2
  d. 2  3  4
  e. 2  2  2  2
 
  What will be an ideal response?

[ergserg]

Answer to Question 1

A

Answer to Question 2

a: 2 IVs; 2 levels for the first IV; 2 levels for the second IV
b: 2 IVs; 2 levels for the first IV; 4 levels for the second IV
c: 3 IVs; 3 levels for the first IV; 2 levels for the second IV; 2 levels for the third IV
d: 3 IVs; 2 levels for the first IV; 3 levels for the second IV; 4 levels for the third IV
e: 4 IVs; 2 levels for the first IV; 2 levels for the second IV; 2 levels for the third IV; 2 levels for the fourth IV