diff --git a/src/statistics.py b/src/statistics.py
index 9039d3f..9d2694d 100644
--- a/src/statistics.py
+++ b/src/statistics.py
@@ -38,7 +38,7 @@ def bh_fdr(pval):
 
     # calculate the needed alpha
     n = float(len(pval))
-    pval_adj = np.zeros(n)
+    pval_adj = np.zeros(int(n))
     i = np.arange(1, n+1, dtype=float)[::-1]  # largest to smallest
     pval_adj = np.minimum(1, cummin(n/i * pval_array[::-1]))[::-1]
     return pval_adj[original_order]