Figure 1 shows the quarks/(quarks+gluons) ratio as a funciton of partonic pt for biased and unbiased samples.  It is difficult to see a potential trigger bias in the low partonic pt bins(<15 GeV/c) due to their large uncertainties.  Therefore, the 4 lowest partonic pt bins were added together into a single bin and the next 3 lowest bins were added together into another bin to make the plot in Figure 2.  The resulting uncertainties are much lower for these bins, but I still do not see an obvious trigger bias effect.   

Figure 1:  quark/parton ratio as a function of partonic pt as shown in my last blog entry

Figure 2:  From Fig. 1 the 4 lowest partonic pt bins were added together into a single bin and the next 3 lowest bins were added together into another bin