7.1.3 Experimental Designs

• What are the three main types of experimental designs?

  Independent groups, repeated measures, matched pairs
• Independent groups design avoids order effects
• Repeated measures design requires fewer participants than independent groups design.
• Why is it difficult to use matched pairs design effectively?

  Requires more participants
• Repeated measures design controls for individual differences
• Order effects are a limitation of repeated measures design.
• Steps to conduct an independent groups design

  1️⃣ Assign separate groups to conditions

  2️⃣ Ensure each participant experiences one condition

  3️⃣ Avoid order effects
• Independent groups design requires more participants
• Repeated measures design reduces the number of participants needed compared to independent groups design.
• What is the main advantage of using an independent groups design?

  Avoids order effects
• Repeated measures design controls for individual differences.
• Repeated measures design exposes the same participants to all conditions
• What is a limitation of repeated measures design?

  Order effects
• Counterbalancing is used in repeated measures design to reduce order effects.
• Independent groups design avoids order effects
• What is a limitation of independent groups design?

  Requires more participants
• In matched pairs design, participants are paired based on relevant key characteristics
• What is a limitation of matched pairs design?

  Difficult to match pairs
• Matched pairs design eliminates order effects.
• Match the experimental design with its key characteristic:

  Independent Groups ↔️ Avoids order effects

  Repeated Measures ↔️ Controls individual differences

  Matched Pairs ↔️ Reduces both individual differences and order effects
• Steps to choose an appropriate experimental design

  1️⃣ Avoid order effects

  2️⃣ Control for individual differences

  3️⃣ Consider sample size

  4️⃣ Assess practicality
• Order effects are not present in matched pairs design.
• Why is matched pairs design suitable for evaluating stress-reduction techniques?

  Reduces practice effects