What happens if every X value is identical?
Vertical lines cannot be expressed as y = mx + b, so the slope is undefined and the calculator will ask for more varied X values.
Step-by-step walkthrough
Linear Regression Calculator Guide
Use this companion guide beside the interactive calculator to make sure you understand the “why” behind every click. Each section includes the classroom explanation, student-friendly language, and quick practice prompts.
Before you start
Collect the data points listed below and double-check their units. Keeping an organized “givens” list is one of the fastest ways to reduce math errors and impress exam graders.
- regression
- trendline
- slope
- prediction
Detailed procedure
Step 1
Enter X values separated by commas, spaces, or new lines.
Step 2
Enter the matching Y values in the same order and length.
Step 3
Optionally set an X value to forecast so the tool returns ŷ for that input.
Teaching & troubleshooting tips
Can I enter blanks or text?
Non-numeric tokens are ignored, so you can safely paste spreadsheet columns that contain labels or missing values as long as both lists stay the same length.