EV's Revised Fuel Economy Survey Thread

[Ever Victorious]

OK... had some more responses come in, so we're getting closer to some preliminary results. Keep your surveys coming in! Especially need to hear from 4AT and 6MT owners!

Clarifications that I need to make on the survey (some are repeats from the previous thread):

1) This survey must be conducted over 5 consecutive tanks. This is what the main odometer reading column is for.

2) The actual fuel economy is calculated off of the total from the trip odometer reading and fuel tank fill-up readings. BOTH of these are needed to the tenths digit. Because of how significant digits work in math/statistics, omissions of the tenths digit from either of these can NOT be made up with use of a hundredths digit from the other one.

3) With regard to the commute speed, I want to know what the average speed of your commute is, if you have one. Since this is how MOST of us spend the bulk of our fuel, it is important to track this speed, not the maximum speed you cruise at (unless the two happen to be the same).

4) There has been a case where a cell was not calculating or was dropping a digit. If this occurs, let me know and tell me from your hand-written copy (you should be printing this and carrying it with you!) what the correct value for the cell is. This is caused by corruption during transmission. My original sheet works in all cells, and this has only occurred once.

New information:

The more data, the better. If you have already participated in the survey and want to give me more data, clear off your form (or request a new one), print it out and keep another 5 tanks of data and send it back.

Again, I especially need more participation from 6MT and 4AT owners.

As of this date, I have had 6 CVTs, 2 6MTs, and 1 4AT submit data.

Thanks for your participation... any further questions?

[XterraVersa]

This is in response to your rejection of my data. You state there can be a difference of 0.2 mpg when I didn't give you data to the tenths of a mile. This is not the case with my data. I have recorded the odometer reading every time I filled up. The way your spreadsheat is setup, the error in the 1st & 5th odometer reading can make a difference. The odometer is accurate to within 0.5 miles, so the maximum error using 2 readings is +/-1 mile.

Now lets look at how insignificant that is. If you use my last five data points, I went 2012 miles & used 53.631 gallons. That equates to 37.5156... mpg. Rounding to 4 significant digits yields 37.52 mpg. 2012 is 4 sig digits, 53.631 is 5 sig digits, you use the smaller to report in division. After 1000 cumlative miles you have 4 sig digits and the accuracy you wanted.

Just to compare errors lets take into account the MPG

-1 mile (2011 miles / 53.631 gallons) = 37.497... mpg. Rounding to 4 significant digits yields 37.50 mpg

+1 mile (2012 miles / 53.631 gallons) = 37.534... mpg. Rounding to 4 significant digits yields 37.53 mpg

So my mpg error over five tanks is +/- 0.015 mpg (+/- 0.040%) This is not significant.

Now lets look at all my data points, I went 5597 miles & used 149.59 gallons. That equates to 37.416... mpg. Rounding to 4 significant digits yields 37.42 mpg.

-1 mile (5596 miles / 149.59 gallons) = 37.422 ... mpg. Rounding to 4 significant digits yields 37.42 mpg

+1 mile (5598 miles / 149.59 gallons) = 37.409 ... mpg. Rounding to 4 significant digits yields 37.41 mpg

So my total mpg error is +/- 0.005mpg (+/- 0.013%) This is even less significant.

I will give you a single tank can have an error of +/- 0.1 mpg when you don't record the mileage to 0.1 miles, but that is why you are asking for 5 consecutive tanks.

It is your choise whether to use the data given to you by others. Just consider what I have just shown you before you reject good data from others in compiling your study results.

[Jemdawg]

You definitely know your statistics, but you're assuming that alpha = .05

But, honestly EV, you should be testing this with a 5% margin of error unless you plan on using this as some sort of official document. A 95% level of significance should suffice for this type of survey.

[Ever Victorious]

Be that as it may (plug .9 onto the end of all of your trip odom readings on the spreadsheet and you will see what I mean... .2 mpg).. you are still missing the point.

CONSISTENT DATA.

If you are participating in a study or survey at the University of Whatever, failure to comply with their guidelines gets your data kicked. Without any notification.

I am at least giving you a chance to correct the way you are recording data for the purpose of this survey (and that's all this is for... for this survey, what you do with your own data is up to you) so that it is recorded in the SAME MANNER as everyone else.

If you do not wish to comply, your data will be kicked. Period.

There will be no further discussion on this topic. The survey was formed, the survey will be conducted the way it was designed. No ifs ands or buts.

[Jemdawg]

BTW, I'm in for this survey, e-mail me a spreadsheet please.

[Ever Victorious]

Sent. You've got mail.

[MIdnkight-lude]

w00t i am one of the 2 6mt. :p

now to fill up another 5 tanks, haha maybe i will have the data soon if i head to vegas again.

[Ever Victorious]

There are now 3 6MTs that have submitted data. Hehehe..

[c5neb]

Be that as it may (plug .9 onto the end of all of your trip odom readings on the spreadsheet and you will see what I mean... .2 mpg).. you are still missing the point.

CONSISTENT DATA.

If you are participating in a study or survey at the University of Whatever, failure to comply with their guidelines gets your data kicked. Without any notification.

I am at least giving you a chance to correct the way you are recording data for the purpose of this survey (and that's all this is for... for this survey, what you do with your own data is up to you) so that it is recorded in the SAME MANNER as everyone else.

If you do not wish to comply, your data will be kicked. Period.

There will be no further discussion on this topic. The survey was formed, the survey will be conducted the way it was designed. No ifs ands or buts.

Just drive, fill and submit !!!!! Enuf said!!!

[Ever Victorious]

Just drive, fill and submit !!!!! Enuf said!!!

Yeah, what he said.

[SPFDRum]

Thanks EV. I'll start at my next fill.

[Ever Victorious]

Thread closed, new thread being started... with some results.