- Last Time: Testing the difference in two
means (the case of unequal variances.)
- Example handout
- Heights of NKU students: males
versus females.
- T-test for difference in means of heights - reject
Ho of no difference
- T-test for difference in means of distances - fail to
reject Ho of no difference
- In the case where the
standard deviations are unequal,
- the change is slight to the standard error
- the change is great to the degrees of freedom (we lose
additional degrees of freedom)
- At this point is hard to say when to say they're unequal
(just eyeball it!)
- Return homework 12.4
- Next time (Thursday): Collect problems 13.1-2
- Questions about old stuff?
- More examples of difference in mean for independent samples:
- Today: The difference between two means (paired samples)
- Paired (matched) samples
- The variable is the difference between a matched pair
- Reduces to a standard t-test on the variable
XD, the difference in the pair
- Example: 13.68,
p. 425
- Example: 13.69,
p. 425
- Try matched
- Try unmatched!
- Next time: More on paired
samples and inference about the difference of two means
Website maintained by Andy Long.
Comments appreciated.
