a) Determination of nominally-significant markers Nominal p values that come from “t” (for pooled data), “χ2” (for individual genotype frequencies) or “ρ” (for correlational approaches) statistics delineate the nominal significance of the differences between disease and control groups for each SNP. For pooled assessments, proper definition of the pool to pool variability is crucial for proper assignment of the appropriate nominal t value. However, the continuous resuslts that come from pooled datasets do provide the additional statistical power characteristic of statistics based on continuous measures.
