Beating a Dead Horse: The Great Torque vs. Horsepower Debate

So this thread by ddd4114 made me want to calculate the average horsepower that my car makes since average horsepower means more than peak horsepower.

Calculating average horsepower would have been easy if I had the formula for the line on the dyno plot because then I'd just take the integral of that line to find the area under the curve and divide that value by the rpm range (in my case 7200-2000=5200). Except I didn't have the formula for this line and didn't know of any programs that could generate it. Since I was just wanting a rough estimate of the average horsepower I decided to just transcribe the dyno plot onto a sheet of graph paper and enter in the horsepower values into Excel with their respective rpms. I used the trapezoid rule as opposed to the rectangle rule, just so I wouldn't be too far off.

So the trapezoid rule:

∫f(x)dx≈(b-a)*[(f(a)+f(b))/2]

or

(2200-2000)*[(32+37)/2]=6900

I went up by increments of 200 starting at 2000 (where the dyno run started) up to 7200 (where it ended).

Using Excel's handy autosum feature I was able to quickly calculate the sum of all these values: 691600

This obviously isn't my average horsepower lol I needed to divide this number by the rpms, in this case it was 5200

691600/5200=133 average whp from 2000rpm to 7200 rpm

If there's an easier way to do this, cool, but this is how I did it and it makes sense. I think it would be interesting if people would list their average horsepower along with their peak horsepower. In addition, you could find your average horsepower for any rpm range, such as the rpm range that you're in while drag racing e.g. 4800-7200.

Tell me what you guys think, have any of you ever calculated your average horsepower?