To edit, add or hide the summary KPI data at the top of a graph or chart, go to Dashboards (top bar)> three dots (top right of the chart to be edited)>Configure Chart. Move the top button to Chart Name & Settings (top section; right button)>Show summary results at top (toggle on/off)> Use drop down menu and cog icon (below summary results toggle) to edit. 
Save your changes (top right of page) and Exit (top right).