 ### Description

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

Decision on Null Hypothesis

Actual State of Alternate Hypothesis

Interpretation

reject (null false, difference exists)

true (null false, difference exists)

correct rejection of null hypothesis

reject (null false, difference exists)

false (null true, no difference exists)

Type I error

not reject (accept null, no difference exists)

true (null false, difference exists)

Type II error

not reject (accept null, no difference exists

false (null true, no difference exists)

correct non-rejection of null hypothesis