Lesson 16

F Tests for Exclusion Restrictions

Big question

How do we test whether a group of variables can be omitted?

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Big question
Concept
Activity
Quiz

Learning objectives

  • Explain f tests for exclusion restrictions in plain language.
  • Use linear combination correctly in an interpretation.
  • Connect the lesson idea to a formula, graph, Python result, or real example.

Simple explanation

For exclusion restrictions, compare the restricted and unrestricted residual sums of squares and account for q restrictions.

Key terms

linear combination
A weighted sum of regression parameters, such as beta1 minus beta2.
exclusion restriction
A restriction that a group of slopes equals zero.
joint significance
Evidence that a group of variables matters collectively.

Core formula

F=[(SSRr−SSRur)/q]/[SSRur/(n−k−1)]F = [(SSR_r - SSR_ur) / q] / [SSR_ur / (n - k - 1)]

Use plain-language interpretation before algebra.

Example

MLB1 gives students a real-data setting for f tests for exclusion restrictions. The lesson emphasizes inference mechanics and interpretation, not memorized output.

Interactive visual

FStatisticCalculator

Original Module 4 visual for F Tests for Exclusion Restrictions.

wage_sample.csv

y variable

wage

The dependent variable. It is the outcome students want to explain.

x variable

education

The explanatory variable. It is used to describe changes in wage.

Live Python

F Tests for Exclusion Restrictions Python example

F Tests for Exclusion Restrictions Python example

Stdout

Run Python to see results here.

Status / stderr

Ready to run Python in your browser.

Line-by-line guide

  1. Line 1Load a Python library needed for data work or regression.
  2. Line 2Load a Python library needed for data work or regression.
  3. Line 3Load a Python library needed for data work or regression.
  4. Line 5Load the dataset into a pandas DataFrame.
  5. Line 6Create or update a Python object used in the analysis.
  6. Line 7Add an intercept column to the regression design matrix.
  7. Line 8Add an intercept column to the regression design matrix.
  8. Line 9Create or update a Python object used in the analysis.
  9. Line 10Create or update a Python object used in the analysis.
  10. Line 11Create or update a Python object used in the analysis.
  11. Line 12Display a result so students can inspect the output.
  12. Line 13Display a result so students can inspect the output.

Python walkthrough

  1. 1Load the real dataset and keep the variables needed for both models.
  2. 2Estimate unrestricted and restricted models or use statsmodels f_test.
  3. 3Compute or read the F statistic and p-value.
  4. 4Interpret the test as a joint statement about population parameters.

Live notebook

Run this lesson as a notebook

Open an editable notebook cell-by-cell, run Python in the browser, and download the `.ipynb` file for later.

Open live notebookDownload .ipynbDownload .py

Related dataset

BWGHT

Estimated time

25 to 40 min

Packages

pandas, numpy, statsmodels, patsy

Expected output

A regression or inference table with coefficients, uncertainty, and short interpretation notes.

Learning goals

  • Load and inspect BWGHT.
  • Run the Python cells connected to F Tests for Exclusion Restrictions.
  • Interpret the output using F tests and restricted model.

Common errors

  • File not found: check that BWGHT.DTA is installed or use the course data folder.
  • Package import error: use the browser notebook first, then download for local Jupyter if your local packages differ.
  • Column name error: compare your variable names with the dataset variables listed for this notebook.

Dataset path helper

import pandas as pd

df = pd.read_stata("/data/BWGHT.DTA")
df.head()

Interactive activity

FStatisticCalculator

Compute an F statistic

Use SSR values, q restrictions, and residual degrees of freedom.

MLB1

Inputs

Try it yourself

Write one plain-English sentence explaining the main idea from this lesson.

Common mistakes

Check these before you move on.

Return to the lesson assumptions, units, diagnostics, and source evidence to replace this shortcut with a defensible interpretation.

Quick quiz

What is the safest inference focus in F Tests for Exclusion Restrictions?

Quick quiz

Which reporting habit is most important in F Tests for Exclusion Restrictions?

Quick quiz

Why is ATTEND a reasonable practice dataset here?

Key takeaway

F Tests for Exclusion Restrictions turns regression output into evidence only when the hypothesis, assumptions, and magnitude are stated clearly.

Download dataDownload resultsDownload interpretation