A quick overview video on three different levels of measurement -- nominal, ordinal, and interval-ratio variables.
Next time when you feel confused about the levels of measurement, think COFFEE!
This video explains the following:
The level of measurement is about how each variable is measured – qualitative or quantitative -- and how precise each variable is. There are four levels of measurement – nominal, ordinal, and interval/ratio – with nominal being the least precise and informative and interval/ratio variable being most precise and informative. Given a choice, choose an interval/ratio variable, as it gives you more freedom and choice when it comes to choosing an appropriate statistical technique.
Not all statistical techniques and methods can be used to all variables. The levels of measurement help us determine what statistical technique is appropriate to use. For example, if the level of measurement of your variable is nominal (the least precise and informative variable), you can use mode to summarize your variable, but not median or mean. If your variable is an interval/ratio variable, you can use all three mean, median, and mode to summarize your variable.
We don't think too often about how we measure things but the manner in which something is measured makes a huge difference on how much you can discover about the relationships among variables. Basically, the lower your level of measurement for any particular variable, the less you can discover! The key is to following the steps to determine any variable's level of measurement. Don't just guess! Go through the process we describe and determining the levels of measurement of any variable should be a snap!