diff --git a/esda/getisord.py b/esda/getisord.py
index <HASH>..<HASH> 100644
--- a/esda/getisord.py
+++ b/esda/getisord.py
@@ -4,7 +4,7 @@ Getis and Ord G statistic for spatial autocorrelation
 __author__ = "Sergio J. Rey <srey@asu.edu>, Myunghwa Hwang <mhwang4@gmail.com> "
 __all__ = ['G', 'G_Local']
 
-from libpysal.common import np, stats, math
+from libpysal.common import np, stats 
 from libpysal.weights.spatial_lag import lag_spatial as slag
 from .tabular import _univariate_handler
 
@@ -106,7 +106,7 @@ class G(object):
         y = y.reshape(len(y), 1)  # Ensure that y is an n by 1 vector, otherwise y*y.T == y*y
         self.den_sum = (y * y.T).sum() - (y * y).sum()
         self.G = self.__calc(self.y)
-        self.z_norm = (self.G - self.EG) / math.sqrt(self.VG)
+        self.z_norm = (self.G - self.EG) / np.sqrt(self.VG)
         self.p_norm = 1.0 - stats.norm.cdf(np.abs(self.z_norm))
 
         if permutations:
remove math and swap to numpy