Systematic Error

The error we have been discussing so far is a statistical error. It is an error that can be made smaller by simply making more and more measurements of the same type. Another error that occurs all-too-frequently is a ``systematic'' error. For example, in measuring the table top, it may happen that our meter stick was slightly miscalibrated, so it gave consistently large results. We would not be able to correct for such an error by repeating the measurement. We would instead have to recalibrate the meter stick. Sometimes we aren't able to do the recalibration, but are assured by the manufacturer or by some other means that the meter stick agrees with a precise standard to within an error of, say 0.005 m. We might then quote the result of a measurement of the table top by saying it is $3.158 \pm 0.002 {\rm (stat)} \pm 0.005 {\rm (syst)}$ meters, thereby identifying separately the two sources of error.