how about if you're reading your overall health on scale of to where those choices correspond to the categories poormoderategoodand excellentwhat do you thinkthat' good example of ordinal data that' very much like our movie ratings dataand againdepending on how you model thatyou could probably treat it as discrete numerical data as wellbut technically we're going to call that ordinal data what about the races of your classmatesthis is pretty clear example of categorical data you can' really compare purple people to green peoplerightthey're just purple and greenbut they are categories that you might want to study and understand the differences between on some other dimension how about the ages of your classmates in yearsa little bit of trick question thereif said it had to be in an integer value of yearslike or years oldthen that would be discrete numerical databut if had more precisionlike years three months and daysthat would be continuous numerical databut either wayit' numerical data type and finallymoney spent in store againthat could be an example of continuous numerical data so againthis is only important because you might apply different techniques to different types of data there might be some concepts where we do one type of implementation for categorical data and different type of implementation for numerical datafor example so that' all you need to know about the different types of data that you'll commonly findand that we'll focus on in this book they're all pretty simple conceptsyou've got numericcategoricaland ordinal dataand numerical data can be continuous or discrete there might be different techniques you apply to the data depending on what kind of data you're dealing withand we'll see that throughout the book let' move on meanmedianand mode let' do little refresher of statistics this is like elementary school stuffbut good to go through it again and see how these different techniques are usedmeanmedianand mode ' sure you've heard those terms beforebut it' good to see how they're used differentlyso let' dive in this should be review for most of youa quick refreshernow that we're starting to actually dive into some real statistics let' look at some actual data and figure out how to measure these things