A line of best fit shows the overall pattern in a scatterplot and gives a predicted output for each input. If the line is already drawn, find the requested input on the horizontal axis, move up to the line, then read its height on the vertical axis. A nearby dot is an observed result, which may differ from the prediction.
Hints
- Hint 1
The input belongs on the horizontal axis. Find the requested number of minutes there. From that tick mark, which direction should you move to reach the line?
- Hint 2
A dot records an observed result from one day, while the line gives a prediction based on the overall pattern. If the dot and line have different heights at the same practice time, which height does the question ask for?
Step-by-step
Read the drawn line
Step 1Separate the dot from the prediction
No Desmos needed. The line of best fit is already drawn. The horizontal axis shows minutes practiced, so find the -minute tick. The dot above it is at measures. That dot is an observed value, an actual result from one day; the question instead asks for the line's prediction.
- Step 2
Read the line at 30 minutes
Move straight up from minutes to the solid line, then read across to the vertical axis. The line is halfway between and , so it predicts about measures played correctly. For a best-fit prediction, read the line at the given input, not a dot. Choice C.