Figure 1. Grouped box plots of MISE for simulations of stKDE and trKDE.

Box-whisker plots of MISE for different sample sizes and factor levels of ordered variable were grouped together for a clear comparison. The middle bold band inside the box is the 50^th percentiles or median; the bottom and top of the box are the 25^th and 75^th percentiles, that is, the lower and upper quartiles, respectively. The whiskers in the bottom and top are the values of 1.5 inter-quartile range (IQR) times the lower and upper quartiles. The y-axis represents the MISE and the x-axis is the sample sizes for three different levels of ordered time variable, which are 2, 4 and 6 levels in turn from left to right.