Measurement error in repeated length readings

PhysicsMeasurement & UncertaintyAges 15–16

A ruler with an adjustable resolution measures a metal rod repeatedly; each reading appears half a second apart with a zoomed-in view of the scale. Random error scatters the readings around a value, while systematic error shifts the whole cluster away from the true value. The program computes the mean, each reading's absolute deviation, the mean absolute deviation, and adds the instrument error to get the measurement's absolute error, then reports the result as x̄ ± Δx together with the relative error as a percentage.