Question

Given below are two statements
Statement I: Correctness or exactness in measurements is associated with accuracy and not with the precision
Statement II: It is not possible to have precise measurements which are not accurate
In light of the above statements, choose the correct answer from the options given below

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

Use the target analogy to remember the difference:
• Accurate & Precise: All shots are in the bullseye.
• Precise but Not Accurate: All shots are clustered together, but not in the bullseye.
• Accurate but Not Precise: Shots are scattered around the bullseye.
• Not Accurate & Not Precise: Shots are scattered all over the target.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This question tests the understanding of two fundamental concepts in measurement: accuracy and precision.

• Accuracy: Refers to how close a measured value is to the true or accepted value. It is about "correctness".

• Precision: Refers to how close a series of measurements are to each other, regardless of their proximity to the true value. It is about "reproducibility" or "consistency".

Step 2: Detailed Explanation:
Analyze Statement I: "Correctness or exactness in measurements is associated with accuracy and not with the precision".
This statement is true. Accuracy is the measure of correctness. A measurement can be very precise (all readings are close to each other) but completely inaccurate (all readings are far from the true value). For example, a faulty scale might consistently show a 5 kg weight as 5.5 kg every time. The measurements are precise (always 5.5 kg) but inaccurate (the true value is 5 kg).
Analyze Statement II: "It is not possible to have precise measurements which are not accurate".
This statement is false. As explained in the example above, it is entirely possible to have high precision with low accuracy. This scenario is common and often indicates a systematic error in the measurement instrument (like a miscalibration). The classic target analogy illustrates this: if all your shots cluster tightly in one corner of the target, far from the bullseye, your shooting is precise but not accurate.
Conclusion:
Statement I is a correct definition of accuracy. Statement II is an incorrect claim. Therefore, Statement I is true and Statement II is false.

Step 3: Final Answer:
Statement I is true but Statement II is false.