Random Error – upon multiple measurements, will result in readings being scattered around the accepted value. This can be reduced by repeating and averaging results or by plotting a graph and drawing a line of best fit e.g. reaction time, temperature fluctuation, pressure fluctuation
Systematic Error – a consistent error which causes readings to be larger or smaller than the accepted value. This cannot be eliminated by repeating and averaging e.g. zero error, calibration error, parallax
Accuracy – a measure of how far away the mean is from the expected value. This can be improved by reducing or eliminating systematic errors.
Precision – a measure of how close repeated measurements are from each other. Precision is affected by random errors
Absolute Uncertainty – the smallest scale division on a measuring device and is always rounded to 1 s.f. If more than five measurements are taken, the absolute uncertainty can be half the range. The measurement will always be rounded to the same place value as the uncertainty.