The observed number of runs is the number of groups of observations that are above or below the comparison criterion, K. Minitab uses the comparison criteria as a value you specify or the default mean of the observations. The number of runs in the sample helps determine whether the sample is random.
For example, a die is rolled 25 times. The scores are as follows:
Let the comparison criteria K = 3.5. The runs are as follows:
The first run (4 6) has values that are above K = 3.5, the second run (3 2 2 1) has values that are below K, and so on.
The observed number of runs = 10.
The p-value is the probability of observing the absolute value of a standard normal variable that is greater than the absolute value of Z.
If too few observations exist for the normal approximation to be valid, Minitab displays a message. Exact tables are widely available.
Term | Description |
---|---|
Observed | The number of runs in the sample |
Expected | |
Variance | |
A | The number of observations above K |
B | The number of observations below or equal to K |
N | The number of observations |