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Terminology
•
Null hypothesis, H
0
•
The hypothesis of no difference
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Alternative hypothesis, H
1
•
The hypothesis, that there is a difference
•
The expected difference is used to calculate β
•
Significance level, α
•
The risk of rejecting the null hypothesis if it is true
•
Normally 5% (p=0.05 is significant)
•
Statistical power, 1-β
•
The probability of rejecting H
0
if H
1
is true
•
Often 80%, recommended 90%
•
Depends on α and assumed effect size