UGC NET Questions (Paper – 1)

Systematic error is a form of measurement error that biases results in a consistent direction, such as always overestimating or underestimating the true value. Unlike random error, it does not average out over repeated measurements and therefore threatens the validity of conclusions. It often arises from faulty instruments, biased procedures or consistent miscalibration. Because the stem describes a consistent tendency to give values higher or lower than the true value, systematic error is the correct term.

Option A:
Random error arises from unpredictable fluctuations in measurement conditions, leading to variations that cancel out over many observations and primarily affect reliability rather than bias. It does not consistently push measurements in one direction, so random error does not match the description in the stem.

Option B:
Sampling error refers to the difference between sample statistics and population parameters that occurs because only a subset of the population is observed. It is related to sample selection rather than to the behaviour of measuring instruments. Therefore, sampling error is not the right completion here.

Option C:
Systematic error is problematic because it can lead to false conclusions even when large samples are used and results appear stable. Researchers must identify and correct sources of systematic bias to preserve validity. These characteristics correspond directly to the stem, confirming systematic error as the appropriate answer.

Option D:
Estimation error is a broader term referring to discrepancies between estimated and true values, which may result from both systematic and random components. The stem, however, specifically focuses on a consistent directional bias, so the more precise term systematic error is preferable.