A major disadvantage of between-subjects designs is that a. ...

[sheilaspns]

A major disadvantage of between-subjects designs is that
 
  a. the effect of one treatment may alter the effectiveness of later treatments.
  b. participant differences may obscure treatment effects.
  c. one must employ fewer independent variables.
  d. one can use only a single independent variable.

Question 2

Preventing an extraneous variable from becoming a confounding variable by holding it constant can result in a threat to external validity.
 
  a. True
  b. False
  Indicate whether the statement is true or false

[chjcharjto14]

Answer to Question 1

B

Answer to Question 2

True