Static and Kinetic Friction vs Normal Reaction Graphing

[JessiLim]

How do i suppose to determine the uncertainty for the slope of my Static friction against normal reaction graph?
My data for static friction and normal force has the uncertainty of +/- 0.0001
The uncertainty is too small for me to draw airbox/bar in the graph to draw the max and min slope.
Please do help me as this is my first time to write a formal report.

 

[jrmichler]

How did you determine the uncertainty of +/- 0.0001 for both normal force and static friction? How did you measure the normal force? How did you measure the static friction? We need to know this in order to answer your question.