Contents
What is the main difference between RM ANOVA and ANOVA?
A repeated measures ANOVA is almost the same as one-way ANOVA, with one main difference: you test related groups, not independent ones. It’s called Repeated Measures because the same group of participants is being measured over and over again.
What does correlation among Repeated Measures mean?
Higher correlation among repeated measures means that each repeat is adding less information to the first measurement. If the correlation were 1, the repeats are no extra information to the original measurement, and the sample size could be calculated ignoring the repeats.
What is a strength of repeated-measures?
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.
How are multiple comparisons with repeated measures different?
However, the arithmetic is no different is we compare (Mean1 + Mean2 + Mean3)/3 with (Mean4 + Mean5)/2. In other words, we can compare means of means. If you had two control groups and three treatment groups, that particular contrast might make a lot of sense.
What to look for in a repeated measures design?
The main thing to look for is whether the data come from the same sample of people or whether different people provided the data. The definition assumes that exactly the same dependent variable (DV) is being measured in each treatment condition. A “Repeated measures research design” is defined as:
How are repeated measures related to ordinal levels?
Repeated Measures with Ordinal Levels The most common form of a repeated measures design occurs when participants are measured over several times or trials, and the Trial variable is thus an ordered variable. I will take as my example an actual study of changes in children’s stress levels as a result of the creation of a new airport.
Which is the best procedure for multiple comparisons?
Virtually all the multiple comparison procedures can be computed using the lowly ttest; either a ttest for independent means, or a ttest for related means, whichever is appropriate. Certainly textbooks give different procedures for different tests, but the basic underlying structure is the ttest.