Update degrees of freedom in printout

Change the degrees of freedom in the printout from 122 to 123. Additionally,
change the phrase 'ndf' (number of degrees of freedom) to 'dof' (degrees of
freedom) to be more consistent.

README.md

@@ -556,7 +556,7 @@ print("chi^2 from scipy:")
 
 # Call chisquare and print.
 chi2, p = scipy.stats.chisquare(count, fit_count, ddof=dof)
-print("  chi2 / ndf = %g / %d" % (chi2, len(count) - dof))
+print("  chi2 / dof = %g / %d" % (chi2, len(count) - dof))
 print("  p-value = %g" % p)
 
 print()  # print blank line
@@ -569,7 +569,7 @@ chi2 = ((count - fit_count)**2 / uncertainty**2).sum()
 
 # Calculate p-value and print
 p = scipy.stats.distributions.chi2.sf(chi2, len(count) - 1 - dof)
-print("  chi2 / ndf = %g / %d" % (chi2, len(count) - dof))
+print("  chi2 / dof = %g / %d" % (chi2, len(count) - dof))
 print("  p-value = %g" % p)
 
 ```
@@ -586,11 +586,11 @@ Optimal parameters:
   b = 0.841156 +- 0.0193703
 
 chi^2 from scipy:
-  chi2 / ndf = 120.577 / 122
+  chi2 / dof = 120.577 / 123
   p-value = 0.519418
 
 Manual chi^2 test:
-  chi2 / ndf = 120.577 / 122
+  chi2 / dof = 120.577 / 123
   p-value = 0.519418
 ```