Students can work with the Tuva movable line to begin eyeballing an estimation of a linear fit. Using the moveable line tool, students can easily stretch and drag a line to approximate data.

The process of creating a movable line to fit bivariate linear data is fairly simple.

Click on any of the images below to bring you to a data set where you can explore this tool yourself!

**Step 1: Create a Scatterplot**

Drag numerical attributes to each the x and y axes.

**Step 2: Add the Moveable Line**

Choose "Add Movable Line on X-Y" under "Stats." This will add an unfitted, movable line on the scatterplot.

If you would like to change the color of the line, click on the small dot next to the x when the line is highlighted.

Your graph will look something like this.

**Step 3: Adjusting the Line**

Drag the line by its middle to translate the line (shift up, down, left, or right). This changes the intercept.

Drag by the handles at either ends to rotate the line or change the slope.

Drag either handle along the slope of the line to stretch the line.

The parameters of the line get updated dynamically as students drag the movable line in search of a good fit.

**Step 4: Finding the Right Fit**

**Continue to tweak the line until it seems to fit the data. The fitted graph will look somewhat like this:**

**When you hover on the line, the equation of the line will appear, and you can start making sense of the equation and parameters in the context of your data.**