Hi there,
Its based on the Statistics Interval that your custom range falls into.
So using your example and taking 1 hour from a week ago (and assuming it is less than 7 days from the current time) then your statistics points are every 30 minutes and are based on being summed up from the previous Statistics Intervals. So you will be presented with a number of data points (at 30 minute intervals) between this period - interestingly you seem to always lose the first data point if you make the custom interval exact, i.e. 12pm based on your scenario, so need to make the start time 11:59AM to have all the points over the 1 hour period.
Now as to interpretting this, I'll use an export from one of our VMs for the time period you mention:
Image may be NSFW.
Clik here to view.
Assuming you want to try and look at something like %RDY for that period then the formula would be: ((Statistics Interval Duration * Seconds in a Minute * ms in a Second ) / Ready ) * 100
Putting some numbers into this would give the following (using the Interval duration for the period shown above which is 30 minutes): I'll use the Ready Average as my data point so that would give (( 30 * 60 * 100) / 7467) * 100) or 4.15% ReadyTime averaged over that hour.
Now remember this is heavily normalised and as daphnissov mentioned this might not be very helpful depending on what you are looking at or trying to chase.
Does that help? Have I made things more confusing?
