On paper multiple regression is pretty cool. In practice, it’s more of a mess. Here you get a bunch of numbers in a table: coefficients, … Read More

You might spend weeks checking your assumptions, fitting your models, and cleaning your data, only to have your actual predictions fall short (even with a … Read More

So now you’ve got one more variable in your model. And the R-squared go up. This looks good. You’re explaining more of the dataset! That’s … Read More

There’s the coefficients. There’s the intercept. There’s that new data point staring back at you from the screen. And the math? It’s pretty easy, almost … Read More

Covariance is a measure of how two variable change together. It tells you that they’re related, but it doesn’t eliminate the units of measurement. If … Read More

If you believe there is some sort of third-party factor that explains relationship between two variables (e.g., you think discipline, not study time, drives exam … Read More

It’s a mix of continuous and categorical. For example, a student might pass an exam and also get specific grade. Similarly, a doctor might prescribe … Read More

Kendall tau measures agreement between two individuals when they are asked to rank-order a collection of items. For example, it could be job candidates or … Read More

First, you check if your variances are equal (unequal spread invalidates the math), and then you perform an analysis of variance to see if your … Read More

Let’s say you’re testing a new drug on three symptoms simultanously. You get important results for only one of those three symptom. Hooray! But then … Read More