Which scenario describes measurements that are precise but not accurate?

• A. They have little spread but are far from the true value.
• B. They have large spread but are close to the true value.
• C. They are both very close to the true value and have little spread.
• D. They are neither close nor consistent.

Answer: (A)

Precision means how close repeated measurements are to each other, while accuracy means how close those measurements are to the true value. When results are tightly clustered but the cluster sits away from the true value, the measurements are very precise but not accurate. So this describes being precise but not accurate.

If measurements were spread out but near the true value, they’d be accurate but not precise. If they were both close to the true value and tightly clustered, they’d be both accurate and precise. If they’re neither close nor consistent, they’re neither accurate nor precise.