Approximately 3.2% (2,338) of the study subjects did not have information regarding socioeconomic status, so values were imputed using the median value imputation method.
To handle missing data, we tested five methods, including rolling back to a simpler model, excluding incomplete cases, EM algorithm, MI, and median imputation (see Materials and Methods).
A General Linear Model (GLM) was used to perform univariate analysis of variance (ANOVA) with an unbalanced design (accommodating missing data by the method of median imputation) to assess each of six different eye movement parameters (response variables) using the statistical software package Minitab v.14 (Minitab Inc., Pennsylvania, USA).
For all methods, average median imputation accuracies on an individual genotype basis R l 2 – – were not always homogenous across population sub-groups as illustrated in Figure S5, which shows individuals plotted according to the first two principal components of their marker genotypes and color coded according to their imputation accuracy.
Missing OES data were imputed using median imputation.
Missing values were imputed using donors imputation method.
Two methods of imputing missing values, last-observation-carried-forward (LOCF) and the median imputation, were applied for single items missing and for total questionnaire missing at T1 and T2 (those lost to the follow-ups).
After the 2000 census, Utah lost one Congressional seat, and North Carolina, which used the imputation method, gained one, prompting Utah to challenge the use of the method.
Sensitivity of imputation method: An imputation method is required for the derivation of PE.
Multiple imputation is more reliable than single imputation, such as mean or median imputation as it considers the uncertainty in missing values [57, 58].
