I'm no statistician, so excuse me if I'm messed up here.

Looking at the cars that have many entries (HCHII at over 237, PriusII at 692 currently), the PriusII appears to have a standard deviation. But the HCHII looks almost bi-modal to me.

Anyone care to venture why this is? Is it that the HCHII only has 1/3 the data points, and does not have enough points to look "normal", like some of the other vehicles with smaller databases, or is 232 enough points to get a true representation. If so, what do you think is affecting it?

You may want to consider the mileage of the cars that are in the population. I know with my HCH II, there was an appreciable difference when I crossed 3500 miles.

I would be an interesting comparison in the population sets in the miles of the vehicles. We may find a correlation in the two - miles vs. mpg. It could be either engine break in or learning how to drive it......

Just my 2 cents.

It doubt any Honda partisan will agree, but I think Honda-and thr HCH ll has more fanatics than Toyota and Prius. It is hard to read that from the numbers, but those 2 "bumps" you noticed might be a hint of just that.
A Honda buyer is more likely to be a committed mpg fan than a Prius buyer, therefore you are going to have a "bump' at above average-the fanatics and near fanatics- and a bump below average-the non fanatics who bought it because it is a reliable vehicle that gets good mpg, but don't really see it as a competition.
Toyota Hybrid -Prius-buyers just aren't as committed as Honda buyers. No one "loves" Toyota in the same way folks "love" Honda.Someday,I will make an effort to prove this, but not today.
Luck,Charlie

That is weird. Have you considered importing the data to Excel and only looking at the data of those with 4 or more tank entries?

This will eliminate the likly out liers and give you a chance to concentrate on those who are making regular contributions. I would expect their data entries to be more accurate.

If the bi-modal curve persists, start looking for a variable that may be associated with one or the other humps. You may be on the verge of finding some previously undocumented phenomina.

GOOD LUCK!

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Is it perhaps time to bring back the "I love what you do for me, TOYOTA!" commercials?

VERY quick glance impressions:

1) lots and lots of low-tank contributors starting at 0 miles. Initial tanks, showing the car off to friends, experimenting, etc. Those under 4-5 tanks or 3-4K miles need to be tossed out of this analysis.

2) The bins are in 3mpg segments- that's a wide range. The fact that one covers to just over the hwy estimate, and the other is 15% under it may be explained by this:
- The upper peak may be representative of folks who bought the car specifically for their commute/highway driving mpg, and are achieving just that. I would fall into that category- 30 out of 33 miles of my commute are open highway.
- The lower peak is possibly where the 'true' average driver is- using the car as a family car, and mixing in a lot of errands/city driving?

The TCH data is worth keeping an eye on- it might start to exhibit the same behavior as its set grows?

Here's a closer look at the FE of the HCHII.

Also, here is a link that shows the number of tanks at the various FEs.
http://www.greenhybrid.com/share/fil...HIIFEtanks.JPG

Bob,
I've lost track of the thread that discussed how to download to Excel. I seem to remember it from several months ago, but can't find it. Can you point me to it?
Thanks.

I'm not sure if this is the best way, but this is what I did. Select and copy all the entries for a given vehicle. Paste them into notepad and save as a txt file. Then go into excel and open the txt file.

I don't remember the thread. I just selected the data from the web page, I'm using Firefox, did a copy and pasted it into an empty Excel spreadsheet. If it doesn't work for you, contact me via e-mail and I'll e-mail the file as an attachment.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.