Question 854·Easy·Math

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Which choice could be an equation for a line of best fit for the data in the scatterplot?

A line of best fit follows the overall pattern of the dots. If the dots form a straight trend, enter their coordinates in a Desmos table and fit a line. Then check the slope, which tells how much the line rises per step right, and the value at $x=0$ . Matching only one of those features isn't enough.

Hints

Hint 1
Each dot is a data pair: an $x$ -coordinate and its matching $y$ -coordinate. Read the coordinates from the numbered axes, then put each pair in the same row of a Desmos table.
Hint 2
In $y=mx+b$ , the slope $m$ tells how much $y$ changes when $x$ increases by $1$ . The value $b$ is $y$ when $x=0$ . Check both numbers against the dots.

Step-by-step

Fit a line to the plotted points
Step 1
Enter the dots as coordinate pairs
Read each dot against the numbered axes: $(0,1)$ , $(1,3)$ , $(2,5)$ , $(3,7)$ , $(4,9)$ , and $(5,11)$ . Enter them in a Desmos table, keeping each dot's $x$ - and $y$ -coordinates in the same row. Desmos plots the six points in a rising, straight pattern.
Step 2
Fit the line and read its two numbers
Type $y_1\sim mx_1+b$ beneath the table. The $\sim$ tells Desmos to find the line that fits the dots; under PARAMETERS, it shows $m=2$ and $b=1$ . The slope $m$ matches the dots' rise of $2$ for each step right by $1$ . The value $b$ is $y$ at $x=0$ , matching $(0,1)$ . Check both the slope and the value at $x=0$ . So $y=2x+1$ fits the data. Choice A.

Question 854·Easy·Math

Strategy

Hints

Step-by-step

Lessons that teach this

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Strategy

Hints

Step-by-step

Lessons that teach this