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Week 8 — Regression

In this week, we are learning about linear regression with StatsModels. All the examples will use the StatsModels OLS (ordinary least squares) model, generally with the formula interface.


Introducing Regression

Statistical Modeling


Single Regression

In this video, I introduce single-variable regression.

Slide Clarification

On slide 6, where I show the slope, intercept, and variance in a model, I have extended the plot to include 0 at the left end of the x-axis. This is to highlight the meaning of the intercept. It is important to note that the intercept is where the line crosses zero, not where it crosses the left Y-axis.

Also, when discussing this slide, I am imprecise but make it sound like the unexplained variance is the remainder after projecting the data onto the line. It is the variance remaining after subtracting the line. I am preparing a video for Week 9 that will provide more clarity on this relationship.

Prediction and Inference

Week 8 Quiz

Complete the Week 8 quiz in Blackboard.

Categorical Predictors

Testing Assumptions

Regression Model Assumptions

Read Regression Model Assumptions from JMP.

Multiple Regression

Measuring Prediction Accuracy

Instances and Sampling

Supporting Notebook

StatsModels Examples and User Guide

The following StatsModels pages document its OLS model:

Bootstrapping Linear Regression

Read Bootstrapping for Linear Regression.

Assignment 4

Assignment 4 is due October 25, 2020.