After reading this chapter, you should be able to

• „„Explain how experiments produce evidence of causality.
   
• „„Describe the different ways an independent variable can be manipulated.
   
• „„Explain the importance of control in experimental research and how control is achieved.
   
• „„Explain the different ways of controlling the influence of potentially confounding variables.
   
• „„Explain why some experimental research designs are weak designs and others are strong designs.
   
• „„Compare and contrast factorial and repeated-measures designs.
   
• „„Explain the concept of an interaction effect.