To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results.
- The data must be numeric
- You must have continuous data, such as the weights of packages, or discrete data, such as the number of complaints.
- The sample data should be selected randomly
- In statistics, random samples are used to make generalizations, or inferences, about a population. If your data are not collected randomly, your results may not represent the population. For more information, go to Randomness in samples of data.
- Collect a large enough sample
- The results of the runs test are valid if at least 10 observations exist both above and below the comparison criterion.
- You cannot have missing data between two numeric values in your sample
- If you have any missing values between any numeric values in a column of data, you must remove the missing values because Minitab cannot perform the analysis. However, you can have missing values at the beginning or the end of the column of data.