Slideshow P4: Drawing a line graph

Features of a good line graph

A 'line of best fit' can sometimes be drawn to show the pattern of the plotted points. This may not be a straight line.

This axis should always show the variable which has been measured, and results collected for.

Both axes should have a label and a unit. They should have a regularly spaced number scale and usually, but not always, start from 0.

Points should be plotted accurately by drawing a small cross with a sharp pencil. The centre of the cross must be exactly at the point being plotted.

This axis should always show the variable that has been changed.

Analysing a line graph

• The average of several results is plotted. Unusual results have been discounted.

• There is a clear best-fit line through the points.

• The line shows that if the force is doubled, the distance doubles. If the force is three times, the distance is three times.

• Distance data for other force values would be needed to confirm this relationship.