QX60 Gas vs. QX60 Hybrid Stats

Here’s another look at the real world data in Fuelly. This time, I looked at the underlying data and threw out anything that looked questionable. For the Hybrid QX60, the MPG values are based on 199 fill ups (data points). For the Gas QX60, the MPG values are based on 108 fill ups (data points).

Hybrid QX60
Fill ups = 199
Miles Driven = 62,111.7
Gallons Consumed = 2,982.7
Max MPG = 27.7
Min MPG = 13.5
Ave MPG = 20.8
Std Dev = 2.4 MPG

Gas QX60
Fill ups = 108
Miles Driven = 30,654.1
Gallons Consumed = 1,588.2
Max MPG = 25.2
Min MPG = 14.3
Ave MPG = 19.3
Std Dev = 2.2 MPG

bsnguy said:

Thanks for starting this... so any explanation as to why the std dev is worse when you throw out what your consider to be questionable data?

Click to expand...

Short answer is because there are nearly twice as many data points (and vehicles) for the Hybrid. Each vehicle is unique, and is driven unique. For example, my Fuelly data contains the lowest MPG rating of all QX60s (13.5 MPG), and I have a Hybrid. That particular data point was due to my wife's driving for one week (69 miles total). She takes my youngest daughter to preschool everyday. She has to make two 6 mile round trips in heavy stop an go, neighborhood school traffic, with the A/C on. The first 3 miles are downhill (about a 600 foot elevation change), when the engine is cold and has to run to warm up. Then the next 3 mile are all up hill, 6-8% inclines -- it's a killer on MPG as the data shows. The gas version would get about 11-12 MPG in the same driving conditions. Another QX60 Hybrid driving long distance (all highway miles at a relatively constant speed with no stops) achieved 27.5 MPG off a tank. So those two valid data points represent a large swing on either side of the mean value that effects the sigma value. The extremes in the data weren't as large for the gas QX60s, as there were only 5 of them.


What the Feully data does show is that on average, the Hybrid gets about 10% better fuel economy (2 MPG) than the gas version.


Based on this data, the vast majority of gas QX60s should average somewhere between 17.1 - 21.5 MPG.


Whereas the vast majority of Hybrid QX60s should average somewhere between 18.4 - 23.2 MPG.