If one plots a pdf in specific ranges and then makes a pull histogram, only the upper range is included. Reproducer below.
import ROOT as r
ws = r.RooWorkspace("workspace")
x = ws.factory("x[-10, 10]")
x.setRange("lo", -10, -5)
x.setRange("hi", 5, 10)
pdf = ws.factory("Gaussian::pdf(x, m1[0], s1[3])")
ds = pdf.generate(r.RooArgSet(x), 1000)
fr = x.frame()
ds.plotOn(fr)
pdf.plotOn(fr, r.RooFit.Range("lo,hi"))
pull = fr.pullHist()
c = r.TCanvas()
fr2 = x.frame()
fr2.addPlotable(pull, "P")
fr2.Draw()
c.SaveAs("output.pdf")
output.pdf (14.9 KB)