Another issue with querying the microarray data of any experiment is the lack of full sample information to stratify results; for example, different exposures may be associated with a subset of the samples.
Logistic regression analysis was applied to the Australasian case-control sample set to stratify data according to gender, RF, CCP and SE status using the STATA 8.0 data analysis and statistics software package (StataCorp, College Station, Texas, USA).
In order to have a sufficient sample size to stratify by gender, lifestage, seafood intake, and hepatitis status, we pooled data from 2001 to 2008, the most recent four NHANES cycles with full data available.
The first stage of the sampling procedure was to stratify the population into military and civilians.
It is also important to have population-based or school-based representative samples, with low percentages of loss to follow-up and sufficiently large samples to be able to stratify by specific age.
From this study, we only considered the authors' defined 453-probe signature used to stratify samples into the five known subtypes.
All variants not mapping to coding regions were removed, and the resulting data files were parsed to stratify samples according to non-silent mutation (insertions/deletions, non-synonymous nucleotide variants) status of a given proto-oncogene.
We decided not to stratify the sample according to sexual orientation since it was a convenience and intentional sample, so the sample was not large enough for such analysis.
We used two-stage sampling probability proportional to size to stratify the two WRUAs as primary sampling units.
Multivariate analyses of variance were used to stratify the sample into mild, moderate, and severe pain groups using eight cutpoint models for worst and average pain in the last 24 hours.
