Which type of error remains constant across measurements?

Which type of error remains constant across measurements?

• A. Systematic error
• B. Random error
• C. Both
• D. Neither

Answer: (A)

Systematic error is a bias that stays in the same direction and magnitude across repeated measurements when the measurement method and instrument are unchanged. This constant offset means every measurement is consistently shifted by the same amount, so it won’t disappear just by taking more measurements. For example, a scale that is off by +2 units will always read 2 units high, regardless of how many measurements you take. Random error, in contrast, fluctuates from one measurement to another due to unpredictable noise and variability; averaging many trials helps cancel out random error, but it does not produce a constant bias. So the error that remains constant across measurements is the systematic error.

Systematic error is a bias that stays in the same direction and magnitude across repeated measurements when the measurement method and instrument are unchanged. This constant offset means every measurement is consistently shifted by the same amount, so it won’t disappear just by taking more measurements. For example, a scale that is off by +2 units will always read 2 units high, regardless of how many measurements you take. Random error, in contrast, fluctuates from one measurement to another due to unpredictable noise and variability; averaging many trials helps cancel out random error, but it does not produce a constant bias. So the error that remains constant across measurements is the systematic error.