This section introduces general definitions and background information: a formal description of sample selection bias (Section 2.1), the special case of two-phase case-control studies (Section 2.2), and properties of
biased samples (Section 2.3).
To reduce the undue influence that might arise from a particular randomly generated
biased sample or from a particular random subsample used in our experiments, for each data set, we create 10 such
biased samples and within each
biased sample use 10 repetitions of random selections of subsamples of different sizes.
In other applications of live-capture data, the way to manage bias is less clear and investigators should aim at minimising the bias by using more than one method of capture and apply caution when interpreting the results from possibly
biased samples of individuals.
"How can the IWA's conclusions provide an accurate picture or be truly representative when it is based on such a small and seemingly
biased sample?"
But the commission examined a
biased sample of cases.
I suppose this might provide a
biased sample, though.
Taylor herself acknowledges that her methodological approach has a number of flaws: the sampling framework employed led to a
biased sample, both in terms of gender and of care experience, and there is a lack of quantifiable 'evidence' (which could perhaps have been extracted from case-file records) that could have added weight to the conclusions.
Why would any political candidate present results from a
biased sample? Puh-lease.
For example, the studies have very small sample sizes,
biased sample selection, or lack of control groups.
This led to a geographically
biased sample, unless the population density of males approximately 20-40 years of age happened to correspond with the catchment areas for testicular cancer of the hospitals used for the recruitment of cases, weighted by the number of cases for each one.