Continuous data can be measured on a continuum. Think of it as being able to divide a measure by one half, and in half again, and in half again, – to infinity. Contrast continuous data with discrete data where there are only a finite number of values possible or if there is a space on the number line between two possible values. For example, it’s impossible to roll the 2.3 on a roll of the dice. You can either roll a two or three but nothing in between.
Use: A Six Sigma practitioner should always strive to work upstream (if necessary) to gather continuous data because with continuous data you can get a handle on the magnitude of the problem. If you only have discrete data, you could only tell whether it is good or bad, or whether it passes or fails.