- Last Time: More on testing the difference
in two means (matched pairs)
- Next time: Collect homework 13.4
- Collect homework 13.1-2
- Next test: next Thursday, 4/22.
- Again: If you wish, you may hand in the review exercises (chapters 12
and/or 13) to replace another homework assignment. These will be due at
the time of the test. They should be good study helpers....
- Questions about old stuff?
- Today:
- Another example of the difference between two means (paired samples):
- Note: we're skipping section 13.5, which tests the ratio of
variances (this is how one would decide between an equal variance test and an
unequal variance test). The null hypothesis would be that the ratio is 1 (i.e.,
the variances are equal): if we rejected that, then we would need to use the
unequal variance test.
- Difference in proportions: here's the theory....
- Example: 3.111,
p. 444
- Using pooled p
- Using unpooled p's
- M & Ms
- Did your proportion of browns differ from the 30%
expected? (alpha=.05)
- Is there evidence that different bags had
different proportions of browns?
- Next time: Regression (Section 18.1-3)
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