What is the difference between an independent samples t test and a repeated measures t test?
In an independent groups test, the subjects in the 2 groups or conditions (t test) or 3 groups, 4 groups, 5 groups (or 3 conditions, 4 conditions.) are different people. In a repeated measures case, the same subjects are being tested under different conditions. They are the same people.
Why is a repeated measures design used?
More statistical power: Repeated measures designs can be very powerful because they control for factors that cause variability between subjects. Fewer subjects: Thanks to the greater statistical power, a repeated measures design can use fewer subjects to detect a desired effect size.
Why is independent groups design used?
An independent measures design is a research method in which multiple experimental groups are used and participants are only in one group. Advantages of independent measures design include less time/money involved than a within subjects design and increased external validity because more participants are used.
What is the key difference between an independent groups design and a repeated-measures design?
1. Independent measures / between-groups: Different participants are used in each condition of the independent variable. 2. Repeated measures /within-groups: The same participants take part in each condition of the independent variable.
Why is independent groups better than repeated-measures?
The advantage of this is that individual differences between participants are removed as a potential confounding variable. Repeated measures also requires fewer participants, as data from all conditions is from the same group of participants.
What are the differences between an independent groups design and a repeated measures design?
1. Independent measures / between-groups: Different participants are used in each condition of the independent variable. Repeated measures /within-groups: The same participants take part in each condition of the independent variable.
What are the major advantages of using a repeated measures design compared to an independent design?
The primary strengths of the repeated measures design is that it makes an experiment more efficient and helps keep the variability low. This helps to keep the validity of the results higher, while still allowing for smaller than usual subject groups.