Lecture+7

Experiments and Non-experimental Designs

The Classical Randomized Experiment

• Initial Steps:

  • Begins with sampling; availability sampling often used in lab settings due to participant access challenges

• Stimulus:

  • Essential test factor applied to participants for measuring effects

  • Central to hypotheses affecting the dependent variable and answering the research question

Group Assignment

• Types of Groups:

  • Experimental Group: Receives the treatment (independent variable)

  • Control Group: Does not receive any treatment

  • Essential to have one experimental group for each treatment applied

Randomization and Measurement

• Randomization:

  • Assigning groups randomly to ensure identical conditions between experimental and control groups

• Pretest Administration:

  • Measures responses before treatment; crucial for establishing initial benchmarks

  • Lack of a benchmark hinders evaluating treatment impact

Testing and Experimental Effects

• Posttest:

  • Measures responses after treatment to assess effects

  • Preexperimental and postexperimental measures help determine if treatment had an effect

• Experimental Effect:

  • Indicates response differences from treatment exposure

  • Should show variance in pretest and posttest results in the experimental group, while control group results should remain stable