Therefore the only imputation carried out was based on simple single locus phasing and imputation rules and the segregation analysis procedures of Kerr and Kinghorn [ 18].
Imputations carried out using a misspecified distribution in the imputation model can provide biased estimates of hazard ratios, especially, if the specified distribution of the phase-2 variable differs from the true one in terms of symmetry (log-normal versus normal distribution).
Imputations carried out five times for missing covariate data showed no significant difference in the association between category of delivery of epinephrine and primary outcome (results not shown).
For these variables, to allow for the missing data, multiple imputations (10 imputations) were carried out using the Multiple Imputations by Chained Equations with predicted mean matching.
To satisfy the requirements of intention to treat analysis that all enrolled children should be included in analyses, we carried out imputation of missing data: we imputed age (n=3) using the grade specific mean age.
As such studies improve in their ability to detect the effects of rare variants on phenotype (Li et al. 2013; Lee et al. 2014), it is paramount that the imputation process carried out alongside them generates reasonably accurate imputed genotypes with low-frequency variants.
We attribute this phenomenon to the larger multiple testing burden that is incurred when carrying out imputation, on account of larger number of SNPs that are imputed (and therefore tested).
Genetic imputation was carried out to infer chromosomal segments derived from WAB56 104, CG14, or non-parental varieties.
Genotype imputation is carried out by statistical methods that combine the GWAS data together with a reference panel of haplotypes.
To further evaluate the association of untyped markers tagged by the genotyped SNPs, imputation was carried out by MACH[31] using HapMap Phase II CHB haplotypes as reference.
