Box plots of array variance for three Illumina array types. Box plots of var(earray(x,y)) for Illumina 1M-Duo, 1M-Single, and 660-Quad arrays for normalized and raw data. The 1M-Duo arrays were genotyped in two batches and are plotted stratified by batch ("1M-Duo-Batch 1", "1M-Duo-Batch 2"), as well as by array type "1M-Duo". The number of var(earray) estimates for each array type is: 1M-Duo, n = 45; 1M-Duo-Batch 1, n = 18; 1M-Duo-Batch 2, n = 27; 1M-Single, n = 11; 660-Quad, n = 360. Box plot whiskers are plotted at the lowest datum within 1.5 the interquartile range of the lower quartile, and the highest datum within 1.5 the interquartile range of the upper quartile.