Rancangan eksperimen | Between dan within subjects

Summary

This video provides an insightful overview of two key experimental designs: between-subjects and within-subjects. Between-subjects design involves randomly assigning participants to different groups, with each experiencing a unique condition. This design is beneficial for parallel testing but requires more participants and may introduce confounding variables. In contrast, within-subjects design involves the same group of participants experiencing all conditions, reducing participant variability but potentially introducing fatigue or order effects. The choice of design depends on factors like participant availability, the nature of the experiment, and measurement types, offering strengths and weaknesses that researchers must weigh when planning their studies.

Takeaways

• 😀 Between-subject design involves assigning participants to two or more groups, where each group experiences a different intervention, such as an experimental or control condition.
• 😀 In a between-subject design, participants are randomly assigned to different groups, ensuring that each group experiences only one condition of the experiment.
• 😀 A practical example of a between-subject design: One group of participants experiences high noise levels, and another experiences low noise, and their concentration levels are compared.
• 😀 One of the strengths of between-subject design is that it allows for faster data collection since different groups can experience different conditions simultaneously (parallel testing).
• 😀 A key limitation of between-subject design is that there may be unequal characteristics between the groups, which could lead to confounding variables that affect the results.
• 😀 Within-subject design, on the other hand, involves the same participants experiencing multiple conditions (e.g., high noise and low noise), allowing for comparisons within the same individual.
• 😀 In a within-subject design, there is no need for separate groups, making it advantageous for studies with limited participants or when minimizing group differences is crucial.
• 😀 One advantage of the within-subject design is that it reduces confounding variables, such as individual differences (e.g., IQ, learning speed) since the same person is exposed to all conditions.
• 😀 A potential drawback of within-subject design is participant fatigue, as they are exposed to multiple conditions, which can increase the time spent in the experiment and may affect performance.
• 😀 The choice between between-subject and within-subject designs depends on several factors, including participant availability, the nature of the intervention, and the experimental setting.

Q & A

What is the main difference between a between-subjects and a within-subjects design?

The main difference is that in a between-subjects design, different participants are assigned to different conditions, while in a within-subjects design, the same participants are exposed to all conditions.

Why is the between-subjects design also called an 'independent groups design'?

It is called an 'independent groups design' because each participant is assigned to only one group, and the groups are independent of each other. There is no overlap in participants between groups.

What is an example of a study using a between-subjects design?

An example would be a study comparing the effect of loud noise versus low noise on concentration. Participants are randomly assigned to either the loud noise group or the low noise group, and their concentration levels are compared.

What are the strengths of a between-subjects design?

The strengths include the ability to run experiments in parallel, which can reduce subject fatigue and allow for quicker data collection. It also ensures that each group experiences only one condition, reducing potential biases from previous conditions.

What is a key weakness of the between-subjects design?

A key weakness is that it may not ensure equivalent groups. Despite random assignment, there may still be differences between groups that affect the results, such as variations in participant characteristics, leading to potential confounding variables.

What is the advantage of using a within-subjects design in terms of participants?

The advantage is that fewer participants are required because the same group of participants experiences all conditions, which also helps in controlling for individual differences across conditions.

Can you give an example of a study using a within-subjects design?

An example would be a study where the same group of participants is first exposed to loud noise, their concentration is measured, then they are exposed to low noise, and their concentration is measured again. The change in concentration within the same participants is compared.

What are the potential disadvantages of a within-subjects design?

The main disadvantage is that participants may experience fatigue or carryover effects, where the results from one condition may influence their performance in subsequent conditions, thereby affecting the validity of the results.

How does the choice between a between-subjects and a within-subjects design depend on the nature of the experiment?

The choice depends on several factors, such as the number of participants available, the type of intervention being tested, the nature of the measurements, and whether the experiment requires repeated testing of participants or can be done with independent groups.

What is a confounding variable, and how does it relate to the between-subjects design?

A confounding variable is an external factor that may influence the results of the experiment, making it difficult to determine the true cause of the effect. In a between-subjects design, unequal characteristics between the groups (despite random assignment) can lead to confounding variables that affect the internal validity of the experiment.