The **method of least squares** is a method we can use to find the regression line that best fits a given dataset.

The following video provides a brief explanation of this method:

To use the method of least squares to fit a regression line in Google Sheets, we can use the **LINEST()** function.

The following step-by-step example shows how to use this function in practice.

**Step 1: Enter the Data**

First, let’s create the following dataset in Google Sheets:

**Step 2: Use Method of Least Squares to Fit Regression Line**

We can use the **=LINEST(known_ys, known_xs)** function to use the method of least squares to fit a regression line to this dataset.

To do so, type the following formula into cell **D1**:

=LINEST(B2:B16, A2:A16)

The following screenshot shows how to use this formula in practice:

The coefficients of the regression line are shown in cells **D1** and **D2**.

**Step 3: Interpret the Results**

Using the coefficients from the **=LINEST()** function, we can write the following fitted regression line:

y = 11.55211 + 1.07949(x)

We can use this equation to estimate the value of y based on the value of x.

For example, if x = 10 then we would estimate that y would be equal to **22.347**:

y = 11.55211 + 1.07949(10) = 22.347

**Step 4: Plot the Results**

Lastly, we can plot the dataset along with the fitted regression line.

To do so, highlight the cell range **A2:B16**, then click the **Insert** tab along the top ribbon, then click **Chart**.

In the **Chart editor** panel, choose Scatter chart as the chart type:

Then click the **Customize** tab in the **Chart editor**, then click the dropdown arrow next to **Series**, then scroll down and check the box next to **Trendline**:

The fitted regression line will appear on the scatter plot:

The individual points in the plot represent the (x,y) pairs from the original dataset and the straight line through the data points represents the fitted regression line.

**Additional Resources**

The following tutorials explain how to perform other common tasks in Google Sheets:

How to Create a Correlation Matrix in Google Sheets

How to Perform Logistic Regression in Google Sheets

How to Perform Polynomial Regression in Google Sheets