Solution:
Let the slope of the best fit line be represented by '[tex]m_{best}[/tex]'
and the slope of the worst fit line be represented by '[tex]m_{worst}[/tex]'
Given that:
[tex]m_{best}[/tex] = 1.35 m/s
[tex]m_{worst}[/tex] = 1.29 m/s
Then the uncertainity in the slope of the line is given by the formula:
[tex]\Delta m = \frac{m_{best}-m_{worst}}{2}[/tex] (1)
Substituting values in eqn (1), we get
[tex]\Delta m = \frac{1.35 - 1.29}{2}[/tex] = 0.03 m/s