I have two time matrices of t1=3x250 and t3=3x450 with 3 columns representing hour, minute and second as integers. I also have two vectors X1 and X2 of size 1x450 and 1x250 respectively. I know on the SAME graph want to plot X1 and x2 against t1 and t2 where each observation on x axis would read in format hour:minute:second. Probably very easy to do. Could anybody guide me please?