Which of the following methods is most effective in reducing selection bias during the sampling process?

Explanation: Selection bias occurs when certain segments of the population are over- or under-represented in the sample. Stratified sampling effectively combats this issue by dividing the population into well-defined strata and sampling proportionally from each. This ensures balanced representation, minimizes bias, and provides a clearer reflection of the entire population. This technique is particularly useful in diverse populations, where subgroups may have different characteristics relevant to the analysis. Option A: Convenience sampling often increases selection bias as it does not account for representativeness. Option B: Systematic sampling can reduce bias but may inadvertently introduce patterns if the population is ordered. Option D: Self-selection introduces significant bias as it relies on participant interest, skewing the sample. Option E: Historical data may not be representative of current conditions, leading to bias in conclusions.