To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results. 
 
 
 
 
-  Collect raw data
- The raw data are in one column of the worksheet for each variable (each observation in a separate row). You can have multiple variables, one in each column, and the columns can have different numbers of observations. 
-  Missing values are counted, but not included in the calculations
-  Minitab counts the missing values (*) in each data column, but does not include them in the calculation of the percentages or cumulative counts.