Estimates of the variance of sample-based estimates were calculated as:
denotes an estimated total based on replicate r (with 62 replicates), and
denotes the corresponding estimate based on the full sample.
The formula for the estimated total based on replicate r is as follows:
is the final replicate student weight, and
is the estimate associated with the final replicate student weight.
The standard error of an estimate is estimated by taking the square root of the estimated variance, VarJK().
This estimate of variance is an application of the jackknife procedure.