How to Do Regression on a TI-84 Calculator

Whether you’re studying algebra, AP statistics, or just want to analyze data, this tutorial of TI-84 Calculator will help you get accurate regression results quickly.

What Is Regression?

Regression helps find the best fit equation that explains the relationship between independent (x) and dependent (y) variables. The most common type is linear regression, which fits data to the form:

 y = ax + b

Where:

• a is the slope
• b is the y-intercept

The TI 84 can also perform:

• Quadratic Regression
• Exponential Regression
• Cubic and Quartic Regression
• Logarithmic Regression

Step 1: Enter Data into Lists

Example Dataset:

Steps:

1. Press STAT
2. Choose 1:Edit and press ENTER
3. Enter x-values in L1
4. Enter y-values in L2

Step 2: In TI-84 Calculator Turn On Diagnostic (Optional but Useful)

To display r and r² (correlation and coefficient of determination):

1. Press 2nd then 0 (Catalog)
2. Scroll down to DiagnosticOn
3. Press ENTER twice

Step 3: Perform Linear Regression

Steps:

1. Press STAT
2. Arrow right to CALC
3. Select 4:LinReg(ax+b) and press ENTER
4. Type L1, L2 by pressing 2nd then 1 and 2nd then 2
5. Press ENTER

You’ll get output like:

a = 2
b = 0
r² = 1
r = 1

This means the regression line is:

 
y = 2x

Step 4: Store the Regression Equation (Optional)

To store the equation in Y1:

1. After selecting LinReg(ax+b), type:
   LinReg(ax+b) L1, L2, Y1
2. To insert Y1, press VARS → Y-VARS → 1:Function → 1:Y1

Now the equation is saved in your graphing window.

Step 5: Graph the Regression Line

1. Press ZOOM
2. Choose 9:ZoomStat
3. Your scatter plot and regression line will appear

Make sure the plot is turned on:

• Press 2nd then Y=
• Choose Plot1
• Turn it ON
• Select scatter plot (first icon)
• Ensure Xlist is L1 and Ylist is L2

Other Regression Types

Use the same steps with different regression options depending on your dataset.

When to Use Regression on TI-84 Calculator

• In algebra to model relationships
• In AP statistics to analyze trends
• In science class for data modeling
• For SAT and ACT test prep

Tips and Common Errors

• Always check your data in L1 and L2 before calculating
• Clear old data using STAT → Edit, highlight list name → CLEAR → ENTER
• If regression doesn’t work, make sure your lists have the same length

Conclusion

The TI-84 calculator is a powerful tool for performing regression analysis. Whether you’re modeling linear relationships or more complex curves, you can do it all from the built-in STAT functions.

Now that you know how to enter data, run different regression types, and graph the result, you can handle regression questions with confidence.