diff --git a/AUTHORS b/AUTHORS
index c4b059df..49f500f1 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -32,6 +32,7 @@ Oleksandr Sochka <sasha.sochka@gmail.com>
 Paul Redmond <paul.redmond@gmail.com>
 Radoslav Yovchev <radoslav.tm@gmail.com>
 Shuo Chen <chenshuo@chenshuo.com>
+Yixuan Qiu <yixuanq@gmail.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
 Dirac Research 
 Zbigniew Skowron <zbychs@gmail.com>
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 8ca4565a..c0c0292e 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -50,6 +50,7 @@ Pierre Phaneuf <pphaneuf@google.com>
 Radoslav Yovchev <radoslav.tm@gmail.com>
 Ray Glover <ray.glover@uk.ibm.com>
 Shuo Chen <chenshuo@chenshuo.com>
+Yixuan Qiu <yixuanq@gmail.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
 Tobias Ulvgård <tobias.ulvgard@dirac.se>
 Zbigniew Skowron <zbychs@gmail.com>
diff --git a/src/complexity.cc b/src/complexity.cc
index a4c57c43..24b3ed4f 100644
--- a/src/complexity.cc
+++ b/src/complexity.cc
@@ -194,16 +194,16 @@ std::vector<BenchmarkReporter::Run> ComputeStats(
     CHECK_EQ(run_iterations, run.iterations);
     if (run.error_occurred) continue;
     real_accumulated_time_stat +=
-        Stat1_d(run.real_accumulated_time / run.iterations, run.iterations);
+        Stat1_d(run.real_accumulated_time / run.iterations);
     cpu_accumulated_time_stat +=
-        Stat1_d(run.cpu_accumulated_time / run.iterations, run.iterations);
-    items_per_second_stat += Stat1_d(run.items_per_second, run.iterations);
-    bytes_per_second_stat += Stat1_d(run.bytes_per_second, run.iterations);
+        Stat1_d(run.cpu_accumulated_time / run.iterations);
+    items_per_second_stat += Stat1_d(run.items_per_second);
+    bytes_per_second_stat += Stat1_d(run.bytes_per_second);
     // user counters
     for(auto const& cnt : run.counters) {
       auto it = counter_stats.find(cnt.first);
       CHECK_NE(it, counter_stats.end());
-      it->second.s += Stat1_d(cnt.second, run.iterations);
+      it->second.s += Stat1_d(cnt.second);
     }
   }
 
diff --git a/src/stat.h b/src/stat.h
index 136c3aa8..d356875b 100644
--- a/src/stat.h
+++ b/src/stat.h
@@ -119,18 +119,22 @@ class Stat1 {
     if (numsamples_ == 0) return VType();
     VType mean = sum_ * (1.0 / numsamples_);
     if (stddev) {
-      VType avg_squares = sum_squares_ * (1.0 / numsamples_);
-      *stddev = Sqrt(avg_squares - Sqr(mean));
+      // Sample standard deviation is undefined for n = 1
+      if (numsamples_ == 1) {
+        *stddev = VType();
+      } else {
+        VType avg_squares = sum_squares_ * (1.0 / numsamples_);
+        *stddev = Sqrt(numsamples_ / (numsamples_ - 1.0) * (avg_squares - Sqr(mean)));
+      }
     }
     return mean;
   }
 
   // Return the standard deviation of the sample set
   VType StdDev() const {
-    if (numsamples_ == 0) return VType();
-    VType mean = Mean();
-    VType avg_squares = sum_squares_ * (1.0 / numsamples_);
-    return Sqrt(avg_squares - Sqr(mean));
+    VType stddev = VType();
+    Mean(&stddev);
+    return stddev;
   }
 
  private: