Experimental Designs

Match the following descriptions with the correct experimental design type.

• Independent groups design

• A design where participants are matched based on certain variables.

• Matched pairs design

• A design where all participants experience all conditions of the experiment.

• Repeated measures design

• A design where two separate groups experience different conditions.

• Randomized controlled trial

• A design where participants are randomly assigned to conditions.

Answer explanation

An independent groups design involves two separate groups experiencing different conditions, allowing for comparison without the influence of participants experiencing multiple conditions.

In the context of independent groups, what is a confounding variable?

• A variable that is intentionally manipulated by the researcher.

• A variable that may affect the dependent variable and is not controlled.

• A variable that is the same across all groups.

• A variable that is measured after the experiment.

Answer explanation

A confounding variable is one that can influence the dependent variable but is not controlled by the researcher. This can lead to misleading results, making it crucial to identify and manage such variables in independent group studies.

What is the main advantage of using independent groups in experiments?

• They are more economical than repeated measures.

• They eliminate all confounding variables.

• Order effects are not a problem.

• They require fewer participants.

Answer explanation

The main advantage of using independent groups is that order effects are not a problem. In repeated measures, participants may be influenced by their previous experiences, which can skew results.

A repeated measures design is a design where participants experience (a)   of the experiment.

• one condition
• random conditions
• control conditions
• all conditions

Answer explanation

A repeated measures design involves having the same participants experience all conditions of the experiment, allowing for direct comparisons within individuals and reducing variability due to individual differences.

What is a potential issue with repeated measures designs?

• They require more participants.

• They are less valid than independent groups.

• Order effects may occur.

• They are more expensive to conduct.

Answer explanation

A potential issue with repeated measures designs is that order effects may occur, where the sequence of conditions affects participants' responses, potentially confounding the results.

What is counterbalancing used for in repeated measures designs?

• To increase the number of participants.

• To control for order effects.

• To match participants based on variables.

• To reduce the cost of the experiment.

Answer explanation

Counterbalancing is used in repeated measures designs to control for order effects, which can occur when the sequence of conditions affects participants' responses. This helps ensure that results are not biased by the order of conditions.

What is a matched pairs design?

• A design where participants are randomly assigned to conditions.

• A design where participants experience all conditions of the experiment.

• A design where participants are paired based on variables.

• A design where participants are divided into two groups.

Answer explanation

A matched pairs design involves pairing participants based on specific variables to control for those variables' effects. This allows for more accurate comparisons between conditions, making it the correct choice.

Match the following statements with their corresponding characteristics of matched pairs design.

• Characteristic: Confounding variable control

• It requires a pre-test to be effective.

• Characteristic: Cost-effectiveness

• It eliminates all confounding variables.

• Characteristic: Time efficiency

• It is less time-consuming than other designs.

• Characteristic: Necessity of pre-testing

• It is more economical than repeated measures.

Answer explanation

A matched pairs design often requires a pre-test to effectively pair subjects based on their characteristics, making it a potential disadvantage compared to other designs that may not need this step.

What is the main benefit of using repeated measures designs?

• They require fewer participants.

• They eliminate order effects.

• They are more economical than independent groups.

• They increase the validity of the findings.

Answer explanation

The main benefit of using repeated measures designs is that they require fewer participants. Each participant is measured multiple times, reducing the overall sample size needed to achieve statistical power.

In the context of experimental designs, what is meant by 'demand characteristics'?

• Features of an experiment that allow participants to guess the aim.

• Variables that are intentionally manipulated by the researcher.

• Conditions that are the same across all groups.

• Effects that occur due to the order of tasks.

Answer explanation

'Demand characteristics' refer to features of an experiment that enable participants to infer the study's purpose, potentially influencing their behavior and responses. This can compromise the validity of the results.