# Really Simple Statistics: What is Ratio Data #MRX

Welcome to Really Simple Statistics (RSS). There are lots of places online where you can ponder over the minute details of complicated equations but very few places that make statistics understandable to everyone. I won’t explain exceptions to the rule or special cases here. Let’s just get comfortable with the fundamentals.

Last in the series of 4 types of data is ratio data. Ratio numbers have all the features of the previous numbers we’ve talked about plus one more. So, with ratio numbers, we know that certain numbers are bigger than other numbers (ordinal), and we know that the difference between numbers is meaningful (interval). The single feature that separates ratio numbers from the other numbers is that the number zero is relevant. Here are some examples.

• I bought 5 chocolate bars today. That’s two chocolate bars plus three chocolate bars. Five chocolate bars is five times as many as 1 chocolate bar.
• My buddy Justin Bieber had 1 chocolate bar but he gave it to me. He now has zero chocolate bars and I have six.
• 100% of the treats in my hand are chocolate bars. If I give two of them to Justin, Justin has forty percent of the chocolate bars. And, if I give all six of them to Justin, I now have 0% of the chocolate bars and he has 100% of them.

So here are the important distinctions:

1. Most importantly, the zero makes sense. It is an absence of all things chocolate. It’s not less chocolate or smaller chocolate. It’s zero chocolate. 😦
2. The spaces between the numbers make sense. 4 bars is exactly 1 more than 3 bars.
3. We can tell when I have more bars than Justin. If i can hold bars in both of my hands and Justin only has a bar in one hand, I obviously have more than he does.

It’s that simple!