A line graph, not necessarily ona grid, that shows the general shape of the relationship between two variables.It will not have any points plotted and although the axes should be labelledthey may not be scaled.

Thisis the smallest change in the quantity being measured (input) of a measuringinstrument that gives a perceptible change in the reading.

The interval within which thetrue value can be expected to lie. Whenever a measurement is made, there willalways be some uncertainty or doubt about the result obtained.