function z=glucose_diff_rel_mean(valA,valB)
% for study of regional variability of glucose
% variables should be given as a single column

twovals=[valA valB]
a=abs(valA-valB)
z=mean(twovals,2)
width=a./z
width=width*100
hold on
zz=[z width]
zzz=sortrows(zz,1)
plot(zzz(:,1),zzz(:,2),'o','markeredgecolor','k','markerfacecolor','k','markersize',8)