Paper 2 · Units and Measurement
In measuring a physical quantity, which statement correctly distinguishes a systematic error from a random error?
ARandom errors bias every reading the same way; systematic errors cause scatter around the true value.
BSystematic errors are reduced by averaging repeated readings; random errors are not.
CBoth arise solely from incorrect calibration of the measuring instrument.
DSystematic errors bias every reading the same way; random errors cause scatter around the true value.
Explanation: A systematic error (e.g. a zero error) affects every reading by the same fixed amount, so it cannot be reduced by averaging repeats. A random error causes readings to scatter unpredictably above and below the true value, and averaging many repeats does reduce its effect.
Derived from ZIMSEC Physics Paper 2, June 2003, Q1