diff --git a/sourcestats.c b/sourcestats.c
index 9560eac..bdb07dd 100644
--- a/sourcestats.c
+++ b/sourcestats.c
@@ -384,7 +384,7 @@ SST_DoNewRegression(SST_Stats inst)
   int best_start, times_back_start;
   double est_intercept, est_slope, est_var, est_intercept_sd, est_slope_sd;
   int i, j, nruns;
-  double min_distance;
+  double min_distance, mean_distance;
   double sd_weight, sd;
   double old_skew, old_freq, stress;
 
@@ -395,17 +395,19 @@ SST_DoNewRegression(SST_Stats inst)
       offsets[i + inst->runs_samples] = inst->offsets[get_runsbuf_index(inst, i)];
     }
   
-    for (i = 0, min_distance = DBL_MAX; i < inst->n_samples; i++) {
+    for (i = 0, mean_distance = 0.0, min_distance = DBL_MAX; i < inst->n_samples; i++) {
       j = get_buf_index(inst, i);
       peer_distances[i] = 0.5 * inst->peer_delays[j] + inst->peer_dispersions[j];
+      mean_distance += peer_distances[i];
       if (peer_distances[i] < min_distance) {
         min_distance = peer_distances[i];
       }
     }
+    mean_distance /= inst->n_samples;
 
     /* And now, work out the weight vector */
 
-    sd = sqrt(inst->variance);
+    sd = mean_distance - min_distance;
     if (sd > min_distance || sd <= 0.0)
       sd = min_distance;