If there are only 2 state conditions and you determine that one is improbable, then the other is probably true.
The null hypothesis states that there is no difference between 2 groups.
If the null hypothesis is rejected, then there is a difference between the 2 groups.
If the null hypothesis is not rejected, then there is no difference between the 2 groups.
The decision to reject or not reject the null hypothesis may be valid, or it may be done in error. Such an error may be classified as:
(1) Type I error: reject the null hypothesis when it should have been accepted (there is no difference between the 2 groups)
(2) Type II error: accept null hypothesis when it should have been rejected (there is a difference exists between the 2 group)
Parameters:
(1) decision made with the regards to the null hypothesis
(2) actual situation
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Decision on Null Hypothesis
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Actual State of Alternate Hypothesis
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Interpretation
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reject (null false, difference exists)
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true (null false, difference exists)
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correct rejection of null hypothesis
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reject (null false, difference exists)
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false (null true, no difference exists)
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Type I error
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not reject (accept null, no difference exists)
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true (null false, difference exists)
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Type II error
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not reject (accept null, no difference exists
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false (null true, no difference exists)
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correct non-rejection of null hypothesis
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