Uncertainty may be due to sampling variation in cost and outcome data and non-sampling variation related to the economic model and the evaluation process [ 64].
Without correctness, sampling bias is introduced and sampling variation is increased, sometimes substantially, beyond the unavoidable statistical sampling variation.
If this is a trend, Labour has reason for confidence, but it may just be sampling variation around a constant figure of 31.
Apparent changes in disparities across census tracts may result partly from a higher level of sampling variation and bias due to the smaller sample.
All four of the results for England are up on the previous round [2011], though mostly by a marginal amount, either within the range of sampling variation or simply regaining the loss that was suffered between 2007 and 2011.
A fixed effects meta-analysis was used under the assumption that SNPs have one true effect size and that any differences between studies were most likely to be due to sampling variation.
Results of any sample are subject to sampling variation.
Our main concern was uncertainty due to sampling variation.
But there is in any case no measurement of representativeness, and indeed no estimate of sampling variation within times as a baseline against which to compare sampling variation between times.
Added to that, public opinion polls naturally fluctuate from week to week, making it hard to distinguish sampling variation from a small-but-real shift in opinion.
Therefore, as with histologic assessment, this discrepancy could have been caused by biopsy sampling variation.
