A line of best fit gives predicted outputs on a scatterplot; dots show actual measurements. When the line has an equation, enter it as a function in Desmos and evaluate it at the requested horizontal-axis value. Use the line, not a dot at the same input, for a prediction. Check that you entered the requested input, not a nearby one.
Hints
- Hint 1
A prediction comes from the line of best fit, while a dot records what actually happened. If a dot and the line have different heights at the same volunteer count, which height does the question ask for?
- Hint 2
The label on the line gives a linear function, . Here counts volunteers. Replace with the requested volunteer count to find the predicted number of bags.
Step-by-step
Evaluate the line of best fit
Step 1Choose the line rather than the dot
The dot at is one observed measurement: what the club collected. The question asks for a prediction from the line, which need not pass through that dot. Read the line's label, , for the prediction.
- Step 2
Enter the model in Desmos
Type in Desmos, using for the line's output . Desmos graphs the same straight line. The function now holds the given model for the next step.
- Step 3
Find the prediction for five volunteers
The requested input is volunteers. Type on the next line. Desmos prints , so the line predicts bags collected with volunteers. Choice C.