simpler understanding to "average" in demographics I am trying to understand "Graph 7a: HES average 24-hour electricity use profile for owner-occupied
homes, England 2010-11" in United Kingdom housing energy fact file, especially the definition of "average".

To make it simple, assume there are 3 families in that stats, consider the peak, around 5:00 pm - 7:00 pm.
the average value is around 710 Watts, could it be interpreted as

those 3 families consumed 900*2, 800*2, 430*2 respectively, in watt-hours.

$\dfrac{(900*2+800*2+430*2)}{2*3}$, the denominator part represents 2 hours and 3 families.
the whole piece illustrate how average defines.
Is my understanding correct?
 A: The graph is rich in detail, my advice, less focus on the concept of average, and closely examine the modes and timing thereof in the graph to assess information content and accuracy of the data.
I once visited an island that was a country. Interestingly, there hardly any middle-class income people, just low and very high income (a bimodal distribution, which is also common to data with a sinusoidal pattern). As such the 'average' income in that country relates to no-one (like lower high income?). 
In the graph of interest note that general heating has 3 peaks as does cooking with explainable peaks at 8 AM (breakfast), 12:30 noon (lunch) and 6 PM (dinner). Electric shower use has two associated peaks with mornings generally preferred over evenings. As expected, lighting related to electricity consumption witnesses a sharp decline after 10 PM as most people apparently prefer to sleep with the lights off. 
The data is complex composed of parts that have varying modes and at least a skewed distribution of consumption (like audio-visual devices where the mean and median consumption appears to be late afternoon, no sharp peak with major consumption plateau occurring between 6 PM till 10 PM). Less informative are mean statistics here.
