Linear Regression

What Is A Statistical Model

On a deep-down level -- sometimes on a surface level as well -- stats teachers are Math People. And Math People love to bandy around abstract terms like "statistical model" when they could have just said "equation of a line that kind of goes through the middle of that scatter plot of data." But hey, that's what I'm here for, to use words that actually make sense to normal people!

Linear Regression Explained (Vocab)

If you're confused by this whole linear regression thing and only have time to watch one linear regression video, this is the one. Instead of walking through all the minutia of doing these on a calculator, I take a step back and explain what it is we're trying to do with regressions, how to use them, and what some of the vocab means. Armed with that info, you'll understand how all the other linear regression videos fit together.

Linear Regressions On Your Calculator

This video covers the nuts and bolts (and button presses) you'll need to do everything about linear regressions on your TI-84: entering data, graphing the scatter plot, calculating the regression line coefficients, graphing the regression line, and making "predictions" using the regression line you just calculated. Fun!

Standard Error of Linear Regression

This video explains "standard error", a.k.a. σest or sest: what it means, the formula, and how to calculate it on your calculator. It's pretty messy. (Free tip: it's NOT the "s" value that gets spit out when you do a LinRegTTest(), so don't make that mistake!)

Prediction Intervals Using Linear Regression

These aren't covered by all classes, and mostly you'll be creating them using your stats package (calculators don't do them), so this video is aimed at explaining what they are and the formulas involved so that you can understand what your computer is spitting out.

Extrapolation vs Prediction vs Interpolation

If you have one of those stats teachers who goes on the occasional rant about extrapolation, or you're just curious what extrapolation is all about, this video is for you. Don't let anyone accuse you of extrapolating your data!

Residuals In Linear Regression (a.k.a. Unexplained Variation)

This video explains what residuals are, how to calculate them on your calculator, and also how to plot the "residuals plot" on your calculator.

Coefficient of Determination (r2): Explained vs Unexplained Variation

This video gets pretty mathy, so feel free to bail if you get in over your head. The diagram covered in this video tends to get discussed by most profs in class, but it doesn't have much use other than in proving stuff or laying the groundwork for advanced stats classes. So while it's a good concept to understand for intro to stats students, ask your teacher if it's going to be on the test before you go beating yourself up over it.

Method of Least Squares Explained

This is just a quick explanation of what is meant by "least squares", and why they're squaring everything.