Random sampling reduces bias – UGC NET Question

Random sampling gives each unit in the population a known, often equal, chance of being selected, which makes the selection process impartial. This greatly reduces systematic bias in the composition of the sample because personal judgment and convenience are minimised. While it does not completely eliminate all error, it helps ensure that differences between the sample and population are mainly due to chance. Therefore, the correct effect on selection bias is that random sampling tends to reduce it.

Option A:
If random sampling were to increase bias, it would defeat its main purpose in scientific research. The entire rationale for using random methods is to minimise systematic distortions in the sample. Thus, the option suggesting an increase in bias is conceptually incorrect.

Option B:
Random sampling reduces the likelihood that any particular type of individual is overrepresented or underrepresented for systematic reasons. It supports the use of probability theory to estimate sampling error and build confidence intervals. These features correspond directly to the idea of reducing selection bias as stated in the question.

Option C:
Creating bias would mean deliberately skewing the sample in favour of certain subgroups, which is characteristic of convenience or judgement sampling, not random sampling. Therefore, the suggestion that random procedures create bias is misleading.

Option D:
Ignoring bias does nothing to protect the quality of inferences and would be a sign of poor methodological practice. Random sampling is chosen precisely because it addresses concerns about bias rather than ignoring them, so this option does not fit the role described in the stem.