fix(nanops): make tolerance match order of m2, m3 and m4

Author: Alvaro-Kothe

pandas/core/nanops.py

@@ -1278,9 +1278,11 @@ def nanskew(
     #
     # #18044 in _libs/windows.pyx calc_skew follow this behavior
     # to fix the fperr to treat m2 <1e-14 as zero
-    constant_tolerance = (np.finfo(m2.dtype).eps * total) ** 2
-    m2 = _zero_out_fperr(m2, constant_tolerance)
-    m3 = _zero_out_fperr(m3, constant_tolerance)
+    constant_tolerance = np.finfo(m2.dtype).eps * total
+    constant_tolerance2 = constant_tolerance**2  # match order of m2
+    constant_tolerance3 = constant_tolerance2 * constant_tolerance  # match order of m3
+    m2 = _zero_out_fperr(m2, constant_tolerance2)
+    m3 = _zero_out_fperr(m3, constant_tolerance3)
 
     with np.errstate(invalid="ignore", divide="ignore"):
         result = (count * (count - 1) ** 0.5 / (count - 2)) * (m3 / m2**1.5)
@@ -1376,9 +1378,10 @@ def nankurt(
     # #57972 arbitrary <1e-14 tolerance leads to problematic behaviour on low variance.
     # We adapted the tolerance to use one similar to scipy:
     # https://github.com/scipy/scipy/blob/04d6d9c460b1fed83f2919ecec3d743cfa2e8317/scipy/stats/_stats_py.py#L1429
-    constant_tolerance = (np.finfo(m2.dtype).eps * total) ** 2
-    numerator = _zero_out_fperr(numerator, constant_tolerance)
-    denominator = _zero_out_fperr(denominator, constant_tolerance)
+    constant_tolerance2 = (np.finfo(m2.dtype).eps * total) ** 2  # match order of m2
+    constant_tolerance4 = constant_tolerance2**2  # match order of m4
+    numerator = _zero_out_fperr(numerator, constant_tolerance2)
+    denominator = _zero_out_fperr(denominator, constant_tolerance4)
 
     if not isinstance(denominator, np.ndarray):
         # if ``denom`` is a scalar, check these corner cases first before