Throw out obviously bad data?

[sea_king18]

The other option is to manually set them all to 25 mpg so they register, then see whether I can increase them bit by bit back to 26, 27, 28, 29....

Fortunately I keep my own record of data.

[sea_king18]

Originally Posted by sea_king18

The other option is to manually set them all to 25 mpg so they register, then see whether I can increase them bit by bit back to 26, 27, 28, 29....

Fortunately I keep my own record of data.

Just as well - that solution doesn't seem to work anyway.

[RobertV]

You're vehicle is being considered an outlier simply because of the lack of other users/vehicles that match yours mechanically. Even if just comparing the 2 vehicles that are "Hatchbacks", your 11 fuelups at 29MPG vs the other user's 240 fuelups at 20MPG make you an outlier.
The system isn't ruling your data as wrong, or invalid. It's simply just much higher than the averages of the other users with same year/make/model.
If, for example you had 100 more fuel ups, you'd move from being an outlier, statistically.

Maybe if our system allowed a filter for transmission type, that'd help in this situation. Something we'll need to look at in a future update.

Originally Posted by sea_king18

This vehicle should show a double peak (one for the standards at about 28 MPG, another for the autos at about 21), not a standard bell curve.

It sounds like you have an understanding of what's going on!
If you just add (or rather, when you have) more fuel ups, the graphs will create that double peak... like seen here: http://www.fuelly.com/car/volkswagen/jetta/2015
It's also worth noting that the data generates fresh every hour, therefore no fuelup is an outlier until that hourly query says it is.

Originally Posted by Jay2TheRescue

There are links on the admin side to make Fuelly redo the math on your vehicle, but when I click on them, I get a no permission message. Maybe someone with higher admin permissions than me can try?

That won't affect what sea_king18 is asking about. Those are in place to refresh the profile page. Rarely needed/used though, as everything gets updated with Save/Edit.

[sea_king18]

So what determines an outlier? >2 standard deviations?

[RobertV]

https://en.wikipedia.org/wiki/Interquartile_range

"The interquartile range is often used to find outliers in data. Outliers are observations that fall below Q1 - 1.5(IQR) or above Q3 + 1.5(IQR). In a boxplot, the highest and lowest occurring value within this limit are drawn as bar of the whiskers, and the outliers as individual points."

[sea_king18]

Originally Posted by RobertV

Maybe if our system allowed a filter for transmission type, that'd help in this situation. Something we'll need to look at in a future update.

The other option is that these cars are actually missing an engine type - they're all inline 4s, but only some are turbocharged.

[Hersbird]

There are lots of obvious errors that then get washed into a poor overall average.
Look at this for example 2011 Town & Country Ltd. (Chrysler Town & Country) | Fuelly
what should be a great set of data with supposedly 70,000 miles logged. The average seems great but start to look at the individual entries and you see a more normal 20 MPG. Go way back and suddenly 250 mpg tanks start showing up. Look at the best tank, 320 mpg. unless you are some kind of special prototype, or a scooter, any tank over 100 mpg should be thrown out.
I would bet any tank that is over 3 times the average of the model is some kind of error that should be flagged and not included in any overall averages.

[ackiefer]

Newbie here, hopefully not posting in the wrong thread. In my research for a new vehicle I stumbled upon this profile (Chevy Pickup (Chevrolet Volt) | Fuelly) which is responsible for over 1/3 of the fill-ups for the listed model however it is obviously a truck and not a Volt (given the Volt's fuel tank is less than 9 gallons and the entered fill-ups are for well over 20 gallons). It is another example of an "outlier" that is harshly affecting the average fuel economy for the group.

[Jay2TheRescue]

Originally Posted by ackiefer

Newbie here, hopefully not posting in the wrong thread. In my research for a new vehicle I stumbled upon this profile (Chevy Pickup (Chevrolet Volt) | Fuelly) which is responsible for over 1/3 of the fill-ups for the listed model however it is obviously a truck and not a Volt (given the Volt's fuel tank is less than 9 gallons and the entered fill-ups are for well over 20 gallons). It is another example of an "outlier" that is harshly affecting the average fuel economy for the group.

Thanks for bringing it to my attention. I changed the vehicle type to a Chevy truck, and then had the system ignore the two 100+ MPG fillups.

[Unpaidbill]

Somewhere, shortly after I started using Fuelly, I must have missed a fillup, since all of a sudden my mileage went over 100mpg. Is there any way to delete whatever happened to get the mileage more in line with real life? Page is at Fuelly - Track and Compare your MPG