Given below are two statements. In the light of the above statements, choose the correct answer from the options given below.

Statement I:The standard deviation of a series of repeated measurements estimates the likely size of the chance error in a single measurement.

Statement II:Bias affects all the measurements the same way, pushing them in the same direction.

ABoth Statement I and Statement II are true ✓ Correct

BBoth Statement I and Statement II are false

CStatement I is true but Statement II is false

DStatement I is false but Statement II is true

Correct answer: (A) Both Statement I and Statement II are true

Explanation

Both statements are true about error in measurement.

The standard deviation of repeated measurements estimates the likely size of chance error in a single reading.

Chance error is random, scattering measurements on both sides of the true value.

Bias is systematic, pushing all measurements in the same direction by the same tendency.

Because bias is directional, repeating measurements does not average it away.

Random error can be reduced by averaging many readings, while bias must be corrected at source.

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