Which of the following describes measurements not accurate but precise?

• A. Accurate, precise
• B. Not accurate, not precise
• C. Not accurate, precise
• D. Accurate, not precise

Answer: (B)

Accuracy vs precision is what this is testing. When measurements are not accurate but precise, the results cluster tightly with little spread, showing high precision, but they sit away from the true value, indicating low accuracy. For example, if the true length is 10.0 cm and repeated measurements come out around 9.8–9.9 cm, they’re very consistent (precise) but consistently off from the actual value (not accurate). This often points to a systematic error or bias in the instrument or method. To fix accuracy, you’d calibrate or reference against a standard. To improve precision, you’d reduce random errors and refine measurement techniques, aiming for measurements that both cluster tightly and are centered on the true value.