Box plots of the confidence levels for the class assignment of the APL, t(8;21)-AML, inv(16)-AML and NK-AML Test Set samples according to their leukemic blast load. The white vertical line and circle in the interior of the dark gray box is located at the median of the data. The width of the box is equal to the interquartile distance, which is the difference between the third and first quartiles of the data. The interquartile distance indicates the spread of the distribution for the data. The whiskers (the lines extending from the left and right parts of the box) go to the nearest value not beyond the span from the quartiles, i.e., 1.5 times the interquartile distance from the center of the data. Points beyond the whiskers are considered outliers and are drawn individually, indicated in black (+).