Hi,

I’m currently using pyroot to try to fit my histogram with a normal distribution and output both the mean and standard deviation.

```
f = R.TFile(outfile, "UPDATE")
c = R.TCanvas()
# Get histogram pointer
hist = DiffTrack_Truth_X.GetPtr()
# Define a normal distribution manually based on the histogram's mean and standard deviation
mean = hist.GetMean()
std_dev = hist.GetStdDev()
# Ensure std_dev is not zero to avoid division by zero
if std_dev == 0:
raise ValueError("Standard deviation is zero, cannot fit a normal distribution.")
# Define the normal distribution function using the histogram's mean and std dev
#mean =0 std_dev=1
normal="1/([2]*sqrt(2*pi))*exp(-0.5*((x-[1])/[2])**2)"
x_min=hist.GetXaxis().GetXmin()
x_max=hist.GetXaxis().GetXmax()
f1=R.TF1("normal",normal, x_min, x_max)
# Draw the histogram
hist.Draw()
# Draw the normal distribution function on the same canvas
f1.Draw("Same")
# Add LaTeX labels
lt = R.TLatex()
lt.SetTextSize(0.03)
# Label for additional text (you need to define `latexLabel`)
lt.DrawLatexNDC(0.4, 0.91, latexLabel)
# Format and display mean and standard deviation with errors (you might want to fit this first to get errors)
lt.DrawLatexNDC(0.73, 0.73, f"#mu = {f1.GetParameter(0):.3g} #pm {f1.GetParError(0):.3g}")
lt.DrawLatexNDC(0.73, 0.75, f"#sigma = {f1.GetParameter(1):.3g} #pm {f1.GetParError(1):.3g}")
# Update the canvas and save
c.Update()
c.Write()
f.Close()
```

However it is not drawing the fit, where am I going wrong?

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