Index: lnt/server/ui/templates/v4_graph.html
===================================================================
--- lnt/server/ui/templates/v4_graph.html
+++ lnt/server/ui/templates/v4_graph.html
@@ -157,6 +157,11 @@
           <table class="table table-striped table-hover table-condensed">
             <tbody>
               <tr>
+                <td>Mean() as Aggregation Function </td>
+                <td><input type="checkbox" name="switch_min_mean" value="yes"
+                    {{ 'checked' if options.switch_min_mean else ""}}></td>
+              </tr>
+              <tr>
                 <td>Hide Line Plot:</td>
                 <td><input type="checkbox" name="hide_lineplot" value="yes"
                      {{ 'checked' if options.hide_lineplot else ""}}></td>
Index: lnt/server/ui/views.py
===================================================================
--- lnt/server/ui/views.py
+++ lnt/server/ui/views.py
@@ -7,6 +7,7 @@
 import json
 
 import flask
+from flask import session
 from flask import abort
 from flask import current_app
 from flask import g
@@ -505,9 +506,26 @@
     from lnt.external.stats import stats as ext_stats
 
     ts = request.get_testsuite()
+    switch_min_mean_local = False
 
+    if 'switch_min_mean_session' not in session:
+        session['switch_min_mean_session'] = False
     # Parse the view options.
     options = {}
+    options['min_mean_checkbox'] = "min()"
+    if 'submit' in request.args:  # user pressed a button
+        if 'switch_min_mean' in request.args:  # user checked mean() checkbox
+            session['switch_min_mean_session'] = options['switch_min_mean'] = \
+                bool(request.args.get('switch_min_mean'))
+            switch_min_mean_local = session['switch_min_mean_session']
+        else:  # mean() check box is not checked
+            session['switch_min_mean_session'] = options['switch_min_mean'] = \
+                bool(request.args.get('switch_min_mean'))
+            switch_min_mean_local = session['switch_min_mean_session']
+    else:  # new page was loaded by clicking link, not submit button
+        options['switch_min_mean'] = switch_min_mean_local = \
+            session['switch_min_mean_session']
+
     options['hide_lineplot'] = bool(request.args.get('hide_lineplot'))
     show_lineplot = not options['hide_lineplot']
     options['show_mad'] = show_mad = bool(request.args.get('show_mad'))
@@ -769,8 +787,12 @@
 
             values = [v*normalize_by for v in data]
             aggregation_fn = min
+
+            if switch_min_mean_local:
+                aggregation_fn = lnt.util.stats.agg_mean
             if field.bigger_is_better:
                 aggregation_fn = max
+
             agg_value, agg_index = \
                 aggregation_fn((value, index)
                                for (index, value) in enumerate(values))
Index: lnt/util/stats.py
===================================================================
--- lnt/util/stats.py
+++ lnt/util/stats.py
@@ -25,6 +25,19 @@
     else:
         return None
 
+# Aggregation function in views.py receives input via enumerate and produces a tuple
+def agg_mean(pairs):
+    if not pairs:
+        return (None,None)
+    my_sum = 0.0
+    counter = 0
+    for item in pairs:
+        my_sum += item[0]
+        counter += 1
+    if counter > 0:
+        return (my_sum/counter, 0)
+    return (None, None)
+
 
 def median(l):
     if not l:
Index: tests/server/ui/V4Pages.py
===================================================================
--- tests/server/ui/V4Pages.py
+++ tests/server/ui/V4Pages.py
@@ -424,18 +424,21 @@
     # Check some variations of the daily report work.
     check_code(client, '/v4/compile/daily_report/2014/6/5?day_start=16')
     check_code(client, '/v4/compile/daily_report/2014/6/4')
-    
+
     check_redirect(client, '/v4/nts/regressions/new_from_graph/1/1/1/1', '/v4/nts/regressions/1')
     check_code(client, '/v4/nts/regressions/')
     check_code(client, '/v4/nts/regressions/?machine_filter=machine2')
     check_code(client, '/v4/nts/regressions/?machine_filter=machine0')
 
     check_code(client, '/v4/nts/regressions/1')
-    
-    check_json(client, '/v4/nts/regressions/1?json=True')
-    
-    
 
+    check_json(client, '/v4/nts/regressions/1?json=True')
 
+    # Make sure the new option does not break anything
+    check_code(client, '/db_default/v4/nts/graph?switch_min_mean=yes&plot.0=1.3.2&submit=Update')
+    check_json(client, 'db_default/v4/nts/graph?switch_min_mean=yes&plot.0=1.3.2&json=true&submit=Update')
+    check_code(client, '/db_default/v4/nts/graph?switch_min_mean=yes&plot.0=1.3.2')
+    check_json(client, 'db_default/v4/nts/graph?switch_min_mean=yes&plot.0=1.3.2&json=true')
+    
 if __name__ == '__main__':
     main()
Index: tests/server/ui/statsTester.py
===================================================================
--- /dev/null
+++ tests/server/ui/statsTester.py
@@ -0,0 +1,33 @@
+# Perform basic sanity checking of the V4 UI pages.
+#
+# create temporary instance
+# Cleanup temporary directory in case one remained from a previous run - also
+# see PR9904.
+# RUN: rm -rf %t.instance
+# RUN: python %{shared_inputs}/create_temp_instance.py \
+# RUN:   %s %{shared_inputs}/SmallInstance %t.instance \
+# RUN:   %S/Inputs/V4Pages_extra_records.sql
+#
+# RUN: python %s %t.instance
+
+import logging
+
+import lnt.util.stats as stats
+
+logging.basicConfig(level=logging.DEBUG)
+
+def test_agg_mean(values):
+    if values == None:
+        return stats.agg_mean(None)
+    agg_value, agg_index = stats.agg_mean((value, index) for (index, value) in enumerate(values))
+    return (agg_value, agg_index)
+
+def main() :
+    test_list = [1,2,3,4,6]
+    assert(test_agg_mean(test_list) == (3.2,0))
+    assert(test_agg_mean([]) == None, None)
+    assert(test_agg_mean(None))
+
+
+if __name__ == '__main__':
+    main()