Tegger's real-world oil consumption

I do not see any data missing. There are seventeen sample points. Oil
used and miles driven were estimated for each one. The interval
between data points is reasonable.

How come you reject Tegger's statement that he did not take
measurements for every single 1000 mile interval?

If there was any serious attempt at accuracy, there

What you propose above is double counting of data.

I would cut someone a little slack for not writing this on the chart
that was linked. The guy is a volunteer, donating his time and labor,
after all. Plus Tegger is taking questions and answering them (well
those that are posed with civility, anyway). Or maybe others should
criticize those who do not follow Tegger's suggestion earlier to go to
the BITOG site?

Sure, when stated with civility, this is a good question.

All the data was included, it is just not at the interval you want (an
interval that does not make sense, insofar as the credibility of the
study is concerned).

Data does not have to be gathered at exactly the same interval for a
study to be credible.

 

How come you say he made that statement? All I saw was a statement that
not all the 1000 mile checks were recorded. So what was the basis for
not recording some 1000 mile intervals? Or more important why were those
17 dipstick checks chosen? I can speculate all sorts of possibilities.

Beyond that the mileage shown doesn't jive with 1000 mile intervals. I
see intervals of 2550 1200 1430 1390. So what is one to make of that
given the statement that the oil was being checked at 1000 mile
intervals?

No what I propose is using data that has a likelihood of being accurate
versus data whose accuracy is extremely doubtful.

It doesn't matter how much time and effort was expended. The quantity of
effort is not what make the results credible. I would except the
results of data collected in a single 3000 mile interval if done
correctly to be a more meaningful then doing it incorrectly for 13 oil
change intervals'

Asking nicely makes the question easy to ignore. Calling the study
ridiculous won't change anything the criticism will still be ignored so
it makes no difference at all.

The bottom line, if the amount of oil consumed was not measured in a
reliable accurate way then there really isn't anything meaningful to be
drawn from the data.

I'm not the one who is claiming the oil was being checked every 1000
miles. There are only 3 or 4 data points on the chart that come close
to corresponding with 1000 mile sampling interval. There is no way of
knowing what that or any of the other discrepancies mean except that the
study is just far too sloppy in its methods to expect the results to
mean anything at all.

We haven't seen any data. NADA - NONE - ZIP. There is no data in that
chart. What we have are the results of calculations made from what we
have been told is the data. Both the calculations methods and data
collection methods appear to be highly suspect. It looks like it may be
accurate to say that this engine uses quart every 1400-1700 miles. Any
conclusions beyond that simple one are extremely doubtful.
I suspect his engine is like most other engines - the rate of oil
consumption increases the longer the oil is in the crankcase. However,
you would need extremely accurate careful laboratory testing procedures
to be able to detect any change in rate of consumption in the first 2000
miles after a fresh oil change. The fact that he is consistently finding
a difference in the rate of oil consumption between the first and second
1000 miles is very strong indication that the testing procedure itself
is probably introducing this bias.

-jim

 

If someone says that for the last 42000 miles they have added a quart
of oil at 1600 miles and when they go to change the oil at 3000 miles
the engine is almost down to the add mark on the dipstick, I would then
surmise that engine uses a quart of oil about every 1600 miles.
When I see this chart I surmise that this guy has managed to create a
method that maximizes the uncertainty in what should be a fairly simple
thing to keep track of. His engine uses maybe a quart every 1400 miles
or maybe it's 1700 miles to a quart. Who knows?. That is pretty sad to
go to all that extra trouble and end up knowing less as a result. It's
like an old farmer whose method to determine how many cows he has is to
count all the legs and tails he sees in a field and divide by 5. You may
think that method is absolutely brilliant and I respond that it is
utterly ridiculous. The reality for the farmer who has quite a few cows
is he never really is sure how many cows are in the pasture.

-jim

 

Wow.

You have demonstrated a lack of intelligence, an astonishing lack of
common sense, a failure to grasp simple English, a complete breakdown of
even rudimentary communication skills, and have managed to demonstrate
to even disinterested passers-by that you're a complete ****. Do the
entire world a favor and kill yourself, would you?

If you would just shut up in the presence of your betters, you would
never again utter a sound.


RFT!!!
Dave Kelsen

 

Ah I see. Apparently I missed the "DO NOT DISTURB THE STUPID" sign.
Offend one stupid clown and you have offended them all.

My betters??? Is this still the thread about the guy who made checking
the oil on a dipstick into a comedy routine?

 

I would be suspicious of anyone claiming that they knew what their oil
consumption is within 5% over a 42k mile interval. Why? Because
driving conditions likely play a role as much as measurement error.

I think folks who are not as careful as Tegger should be prepared for
variations in measurement of around 25%. They should not read anything
into supposed increases of say 25% until they have monitored oil
consumption over a long period.

Sure a study could always be done better. But this one is in fact very
well done. Failure to concede this subtracts from a person's
credibility, in my eyes.

There is talk on the net of sudden increases in oil consumption, and
then consumption reduces by a lot. But such observations may in fact
be due to mere measurement error. I think this study helps support
this theory.

You and I came to the same conclusion about what the study said, per
the quotations in my last post.

 

This study and subsequent reporting may be careful. Nobody said it
wasn't careful. You can take a shit very carefully, but you still have
nothing but turds to show for it.

The variations of 25% are a direct result of the invalid methodology
used. If you simply figure out how much the engine used over the entire
oil change interval (3000 miles in this case) you will get a reliable
result. If you use 1.8 quarts in 3000 miles traveled that is 1670mi/qt.
If you use 2 quarts in 3200 miles that would be 1600 mi/qt. Simply
accounting for all the oil used and all the miles traveled and dividing
will give an accurate result and eliminate the wild variations. Doing it
the way shown on the PDF file is lot of extra work that does nothing but
make the result less accurate and more uncertain.

It is just plain stupid to do it by measuring small increments on the
dipstick over varying mile intervals and then averaging the results of
those mi./qt. calculations. To illustrate the stupidity - let's suppose
he had read his dipstick at intervals of 200-400 miles and calculated
the mi/qt for each of those varying mileage intervals and then averaged
those mi/qt calculations. You may call that being more careful, but
would it be more accurate? No it would not! It would produce an even
less accurate result. I suggest you enroll in some remedial Math
education if you can't understand why that methodology is invalid.

That's very funny.

WTF??? You are now claiming that the value of this study is that it is
an excellent example of how one can introduce measurement error?? What
purpose does that serve?

 

I echo what Dave Kelsen said.

 

Hey Jim,

You are dissing a guy who has provided good information for me and
others for quite a while here. Lay off of him. He does more work to make
this newsgroup valuable than just about anyone else.

Tegger,

Please don't be discouraged by his dissing you. Every newsgoup has those
who want to criticize without offering their own work for review.

I appreciate you time and effort here. I know there are many more who do.

Michael

 

Another person heard from who is stupid and proud of it.

In case you haven't noticed I have been posting in response to idiots
who think this study is brilliant. The OP who posted the study gave me
the impression that maybe he wasn't of the same mind as you idiots are.

He wrote:

 

That's a good point, and one I hadn't explicitly considered.

I have noticed, though, that if the stick shows, say, 0.8 low on my paper
chart and I add 0.8, the level goes back up to its position during the
first check for that 1,00 miles. The same thing happens if the level is
down 0.4 on the chart. I therefore had no reason to suspect that the level
might not decline linearly.

But since it's a possible variable that I need to account for (now being
aware of its possible existence), this is something I'm going to have to
confirm.

 

I didn't, unfortunately. See my reply to "jim".

I put the fresh oil into a graduated container and pour it into the engine
from that. This way I can make certain I add exactly what the engine used.
If my measuring and chart are correct, then a reading of x-milliliters low
low ought to be exactly offset by the same amount added back in. And it is,
so far as I can see.

 

It was left out because I didn't think to put it in.

Part of my reasoning for posting this to Usenet and BITOG was to solicit
others' opinions on the test, its methodology, and the report. These I have
received (some a bit irascibly), so thanks for that.

I have updated the PDF to account for the issues that have been brought up
here and in BITOG.

http://www.tegger.com/hondafaq/misc/graph-may28-10.pdf
I had to clear my cache before the updated PDF would show up.

 

I recorded everything I found as precisely as possible. Nothing is
"missing" from the dataset.

However, one record was questionable and was therefore not included: my
very first properly-recorded check gave me a mileage of 2,200. This created
an anomalous spike (that did not occur at any other point in the test). I
therefore decided I'd done something wrong during that particular check,
and excluded it from the results.

 

Thanks.

But "jim" actually did have a couple of good points buried within his
invective. I've adjusted the PDF to address those points. And I'm going to
see if I can determine exactly what is the degree of linearity of the
dipstick readings.

 

An initial check is taken before each test sequence.

But you're only using two data points. I suspect that, as the dataset grows
ever larger, that the difference between your first method and your second
will lessen greatly, and will eventually disappear. That's why sample-size
is so critical to any sort of statistics.

 

This methodology means that there is not a need to do a linearity
check, at least for this study.

I quoted what you wrote above at honda-tech.com . The threads are in
the tech/misc and Acura Integra sections.

Aside, for those trying to post to the BITOG forum: I applied to join
the BITOG forum almost a week ago and still have not been approved.

 

The point I have been making is your PDF file is itself strong evidence
that your measurements and calculations are flawed. I can tell you
there is very little doubt that the error exists. I would estimate there
is a one in a million chance that the measurements and subsequent
calculations shown in the PDF are at all close to correct. I believe the
oil is being consumed at a fairly steady rate. The wild fluctuations are
nothing but evidence that the measurements and calculations are
inaccurate. The fact that the fluctuations are not at all random
suggests that the error is due to a measurement bias. The bias makes it
appear that typically more oil is being consumed in the first 1000 than
in the second 1000. But in reality the general difference that is found
the first and second readings is probably due to something other than
the actual consumption.
Whether you are interested in finding the source of the error is your
call. no one else is in a position to investigate. On the other hand you
can circle the wagons and try to defend the foolishness. It's your call.

One thing to consider is oil at 2500 miles looks different than fresh
oil. And your measurements and calculation entirely depend on how the
oil looks on the dipstick, so that is one possible source of a
measurement bias.

The suspicion that the error comes from the irregular shape of the pan
was based on the assumptions made at that time (which I posted). There
could be a small region on the dipstick where there is a non linearity.
If your first 1000 mile measurement tends to be below that spot and the
second above then you could be getting large difference where in reality
both measurements are close to the same.

I will state my current assumptions based on some new info in case
you're interested:

1) At 3000 miles you change the oil. When you fill with fresh oil the
level on the dipstick is a bit below full.

2) After somewhere in the neighborhood of 1000 miles you infer that it
has used about .7 quarts which would make you think it went around 1400
miles/qt. In reality the engine has really only used .6 quarts at that
point in the cycle which means it has really gone 1670 mi./qt. At this
point you add .7 quarts of oil and that bring it up to tad over full (.1
higher than it started).

3) At around 2000 miles you check the oil and infer from your
measurements that
it has used .6 quarts which means in that interval you think it has gone
1670
miles/qt. But in reality it has used a .61 quarts on this part of the
cycle (pretty much the same as the first 1000 miles). That means it has
actually used 1640 mi/qt. in this interval. You then add .6 quarts and
that brings it back to full mark.

4) At 3000 miles your chart indicates you don't do any
measuring/recording data you just change the oil and repeat the process
which again repeats roughly the same errors.


Notice that I used 1000 mile intervals but your PDF file makes it clear
the 1000 mile intervals is most of the time just a fiction.
Also, there should have been 43 dipstick reading in 42000 miles, but
only 25 of these were recorded. Did you not like what you saw on the
dipstick on those other occasions? n other words. what bias was
introduced by selecting only 40% of the possible samples. What about the
13-14 time the that engine reached the 3000 mile mark? Are we to believe
you never once looked at the dipstick to determine and record how much
was used in the 2000-3000 mile sampling interval?

-jim

 

No sorry doesn't at all work that way. You claim to be trying to
determine how much oil is being used on average. Your method arriving at
that number is grossly unreliable. However your data is too spotty to
actually estimate how inaccurate that method is for this data.

The correct method is easy. If you summed how much make up oil you
added in total plus how much less than full it was at the time of oil
change, you would get a number that represents the total consumption
over the entire 42000 miles. You then make the calculation on that total
consumption and total miles.

Try your method with the IRS. Tell them you are going to average
dollars/day for various periods of income that you selected by some
unknown criteria and in which some of them you earned a lot of money per
day and some periods not so much per day and that you will use that
average of those 17 dollars/day figures as an accurate measure of your
annual income. The idea is so absurd that you probably will even get an
IRS agent to laugh.
You don't have a statistical problem to solve - you have an accounting
problem and you are applying absurd accounting practices.

-jim