treeherder/ui/partials/perf/average.html

<!-- Show standard deviation if >1 run -->
<span class="detail-hint" ng-if="replicates.length > 1"
      tooltip="Runs: &lt; {{replicates.join(' ')}} &gt;
        ({{stddev|displayPrecision}} = {{stddevpct|displayPrecision}}% standard deviation)">
  {{value|displayPrecision}} &#177; {{stddevpct|displayPrecision}}%
</span>
<!-- View for only 1 run (no stddev) -->
<span class="detail-hint" ng-if="replicates.length === 1"
      tooltip="Only one run (consider more for greater confidence)">
  {{value|displayPrecision}}
</span>
<span class="text-muted" ng-if="!replicates || replicates.length == 0">
  No results
</span>