Answer: Solution :
Step 1 :
Make a scatter plot of Lily’s running data.
Step 2 :
To draw a trend line, use a straight edge to draw a line that has about the same number of points above and below it. Ignore any outliers.
Step 3 :
Find the slope of the trend line.
The line passes through points (2, 20) and (4.5, 45).
Use the slope formula.
m = (y2 - y1) / (x2 - x1)
Substitute x1, = 2, y1 = 20, x2 = 4, and y2 = 45.
m = (45 - 20) / (4.5 - 2)
m = 25 / 2.5
m = 10
Step 4 :
Find the y-intercept of the trend line.
Slope-intercept form equation of a line :
y = mx + b
Plug y = 20, m = 10 and x = 2.
20 = 10 · 2 + b
20 = 20 + b
Subtract 20 from both sides.
0 = b
Step 5 :
Use your slope and y-intercept values to write the equation.
Slope-intercept form equation of a line :
y = 10x + 0
So, the equation for the trend line is
y = 10x
Example 2 :
David records the number of chapters and the total number of pages for several books as given below.
No. of chapters
3
4
5
8
10
11
15
17
19
No. of pages
20
44
50
95
90
130
125
170
160
Step-by-step explanation:
