Independent Samples TTest (continued)
This will bring you to a table containing 12 components. For this example,
we will use the means for the Phoneme Deletion task (PD).
We will now go through each component, filling in the
appropriate number using the data in this study.
1. Test significance level, a
Alpha is the probability of rejecting the null hypothesis of equal means
when it is true (the probability of a Type I error).
Suggestion: Enter 0.05, a frequent standard
Acceptable entries: 0.001 to 0.20
**For this example: Shankweiler et al. set a
= .05. So type ".05" in the first box.
2. Onesided or twosided test
A twosided (twotailed) test will reject the null hypothesis if differences
are large and positive or large and negative. A onesided (onetailed)
test rejects the null hypothesis only for differences in a single direction
(positive or negative).
Suggestion: Enter 2, a frequent standard
Acceptable entries: 1 or 2
**For this example: Shankweiler et al. designed
this as a onetailed test. So type "1" in the second box.
