Which outcome is possible in a 2 x 2 factorial design? a. four ...

[notis]

Which outcome is possible in a 2 x 2 factorial design?
 
  a. four main effects and no interaction
 b. four main effects and no interaction
 c. no main effect for either factor but an interaction
  d. four interactions

Question 2

What is the history threat in a single group design?
 
  What will be an ideal response?

[shayla]

Answer to Question 1

c

Answer to Question 2

When some event other than your program occurs at the same time and affects the outcome, we say there is a history threat to internal validity. It's not your program that caused the outcome; it's something else, some other event that occurred between the pretest and the posttest. We refer to this other event as an historical one, because it is something that happens during the course of your study; it, like your program, is an event in history, so to speak.

[notis]

Gracias!

[atrochim]

Great answer, keep it coming