**Exponential regression** is a type of regression that can be used to model the following situations:

**1. Exponential growth:** Growth begins slowly and then accelerates rapidly without bound.

**2. Exponential decay:** Decay begins rapidly and then slows down to get closer and closer to zero.

The equation of an exponential regression model takes the following form:

y = ab^{x}

where:

**y:**The response variable**x:**The predictor variable**a, b:**The regression coefficients that describe the relationship between*x*and*y*

The following step-by-step example shows how to fit an exponential regression model to the following dataset on a TI-84 calculator:

**Step 1: Enter the Data**

First, we will enter the data values. Press STAT, then press EDIT. Then enter the x-values of the dataset in column L1 and the y-values in column L2:

**Step 2: Fit the Exponential Regression Model**

Next, we fill fit the exponential regression model.

Press Stat, then scroll over to CALC. Then scroll down to ExpReg and press ENTER twice.

The following results will be displayed:

**Step 3: Interpret the Results**

From the results we can see that the fitted exponential model is:

**y = 1.727 * 1.651 ^{x}**

We can use this equation to predict the response variable, *y*, based on the value of the predictor variable, *x*. For example, if *x* = 4, then we would predict that *y* would be **12.83**:

y = 1.727 * 1.651^{4} = 12.83

**Bonus:** Feel free to use this online Exponential Regression Calculator to automatically compute the exponential regression equation for a given predictor and response variable.

**Additional Resources**

How to Perform Linear Regression on a TI-84 Calculator

How to Perform Quadratic Regression on a TI-84 Calculator

How to Create a Residual Plot on a TI-84 Calculator