Having more than two levels of the independent variable is ...

[tfester]

Having more than two levels of the independent variable is necessary to
 
  a. detect causal relationships.
  b. control for common-causal variables.
  c. detect nonlinear relationships.
  d. produce adequate equivalence across the conditions.

Question 2

Which of the following statements is true?
 
  a. All experiments must have one or more control conditions.
  b. All experiments must have two or more control conditions.
  c. All experiments must have two or more dependent variables.
  d. Some experiments do not have a control condition.

[maya.nigrin17@yahoo.com]

Answer to Question 1

c

Answer to Question 2

d

[tfester]

Excellent

[cassie_ragen]

Gracias!