Analysis of variance

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Analysis of variance
Problem If you use t tests with an a of 0.05
then the actual a will be 0.05 x of
tests. ANOVA addresses this problem.
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Assumptions
The good news is that ANOVA is fairly robust with
respect to the assumptions of normal distribution
and equality of variance.
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Strain 1 Strain 2 Strain 3 7. 10 15.
15. 12 12. 10 5 11 11 20 13.
9 9. 14. Mean 10 10.33 13.67 Sd
2.828 5.391 2.16 Strain 1 Strain 2 Strain
3 7 10 15 15 12
12. 8. 8. 17
10 9. 11 11. 13.
13 9. 10. 14. Mean
10 10.33 13.67 Sd 2.828 1.862 2.16
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Example 9.1Time to relief of symptoms
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Difference between means is much greater than
difference within groups
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Example 9.2
Means are the same but variances are higher.
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Within treatments variation
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Between treatments variation
This is an estimate of population variance of the
means
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Example 9.3
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Quotes of the day

• The only difference between the Democrats and the
  Republicans is that the Democrats allow the poor
  to be corrupt, too.
• Oscar Levant(1906 - 1972)
• Those who welcome death have only tried it from
  the ears up.
• Wilson MiznerUS screenwriter (1876 - 1933)
• Somebody has to do something, and it's just
  incredibly pathetic that it has to be us.
• Jerry Garcia, (of the Grateful Dead)

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Repeated measures
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