Which of the following are sources of variance?
The within group differences
The error
The treatment
All of the these
Why would you use post-hoc tests instead of planned contrasts?
We are interested in testing all possible comparisons
There is a need to improve the power of the test
We are not interested in testing all possible comparisons
There are not that many comparisons to make
How can you improve the power of your experiment?
Reducing the degrees of freedom for the residual source of variance
Increasing the number of levels of treatment
Increasing the number of participants
All of these
The power of a test is the probability of...
accepting the alternative hypothesis when incorrect
rejecting the null hypothesis when incorrect
accepting the null hypothesis when correct
rejecting the alternative hypothesis when incorrect
Imagine that you are a Clinical Neuropsychologist who works with language difficulties shown by Aphasics resulting from a brain stroke. You are interested in studying the impact of a particular treatment as a function of the time interval between the time of the lesion and the time of intervention. If you want to maximize the power of the study, which groups would you use?
two groups: 1) immediately after the stroke 2) three weeks later
two groups: 1) three weeks later 2) six months later
two groups: 1) immediately after stroke 2) six months later
three groups: 1) immediately after the stroke 2) three weeks later 3) 6 months later
If you take steps to minimize a Type I error, then the probability of making a Type II error is
Cut in half
Unaffected
Increased
Also decreased
