Question 46·Easy·Two-Variable Data: Models and Scatterplots
Which choice could be an equation for a line of best fit for the data in the scatterplot?
For a line-of-best-fit equation, first decide whether the slope should be positive or negative, then estimate the slope using an easy rise-over-run between two visible points. Finally, use where the trend crosses near to choose the correct -intercept.
Hints
Check the direction of the trend
As increases, decide whether the points generally go up or down.
Estimate rise over run
Use two points that are easy to read (for example, the points near and ) to estimate the slope.
Look at the value when
Find the point(s) closest to the -axis to estimate the -intercept.
Desmos Guide
Plot the points
Enter the six points shown in the scatterplot as a table: , , , , , and .
Graph each answer choice
Type each equation from the choices as a line (one at a time or all together) and see which line runs closest through the middle of the points.
Compare slope and intercept visually
Focus on which line rises about 2 units for every 1 unit to the right, and which one crosses near when . Select the matching choice.
Step-by-step Explanation
Estimate the slope and intercept from the plot
The points rise as increases, so the slope should be positive. Using two clear points such as about and , the change in is about when the change in is , so the slope is about 2. The points near are near , so the -intercept is about 1.
Choose the equation that matches
An equation with slope 2 and -intercept 1 is .