Section 5 of 19
Statistical analysis and design weighting
Dhruva Arcot and Subhankar Chakraborty · about 1 minutes
All statistical procedures were performed using the Complex Samples module in IBM SPSS Statistics (Version 28). Analyses incorporated Mobile Examination Center sample weights (WTMEC2YR), masked variance pseudo-strata, and primary sampling units (PSUs). Missing data and age-based exclusions were handled using the Complex Samples subpopulation (SUBPOP) command, which restricts estimation to the analytic subpopulation while retaining the full survey design structure. This approach prevents distortion of population variance and avoids the artificially reduced standard errors that occur when cases are removed through row-wise deletion.