na = [79,  62,  111,  62,  62];
xa = [376,  429,  529,  618,  742];
nb = [211,  56,  162,  134,  167,  235,  174,  167];
xb = [109,  146,  233,  348,  428,  464,  513,  745];
pa = na / sum(na);
pb = nb / sum(nb);

x = sort(unique(randi([10,100],1,6))); lx = length(x);
px = randi([100,500],1,lx); px = px / sum(px);
y = sort(unique(randi([10,100],1,8))); ly = length(y);
py = randi([100,500],1,ly); py = py / sum(py);