Figure 3
From: Extending World Health Organization weight-for-age reference curves to older children
Bootstrap estimates of centile precision: smoothed centiles for girls (A) BMI, weight, and height were first fitted to the original NCHS-R data (N = 11,193). The 95% confidence intervals (CI) were calculated from 1,000 bootstrap samples drawn from the original data with replacement and analyzed in the same way. Each figure displays centiles 0.135, 3, 50, 97, and 99.9, with error bars to denote the corresponding 95% CI at yearly intervals from 5–19y. Similarly, boys (B) BMI, weight, and height centiles were fitted to data on 11,106 boys and CI calculated from the analysis of 1,000 bootstrap replicates.