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Regression Testing Mileage vs Average Temperature

Discussion in 'Gen 2 Prius Fuel Economy' started by TonyPSchaefer, May 25, 2007.

  1. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    So I'm working towards my Six Sigma Greenbelt certification. I decided to perform a regression test using my mileage chart. Below is what I got from Minitab. There are some outliers in the cooler temperatures, but all in all I'm pretty confident that there is a direct correlation between average temperature and mileage.
    [attachmentid=8330]
     

    Attached Files:

    #1 TonyPSchaefer, May 25, 2007
  2. tochatihu

    tochatihu Senior Member

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    Ahhh, polynomial regression with confidence intervals! Way to go, cousin Tony.

    But with temperatures based on oF, I am sure you can appreciate how this equation could 'blow up' at more extreme temperatures (esp. negative ones).
     
    #2 tochatihu, May 25, 2007
  3. F8L

    F8L Protecting Habitat & AG Lands

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    That would support my anecdotal evidence. Anything below 65deg and my milage starts to drop significantly. Above 80deg and I begin to have the ability to see 50+mpg using the same speeds and routes.
     
    #3 F8L, May 25, 2007
  4. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I'm thinking that those outliers might be contributed to things such as highway driving versus city driving or even heater usage. Unfortunately for this example, I did not keep data on those items.
     
    #4 TonyPSchaefer, May 25, 2007
  5. donee

    donee New Member

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    Hi Tony,

    Do not forget about Humidity (less air drag) and Rain (more rolling resistance).
     
    #5 donee, May 26, 2007
  6. berylrb

    berylrb Member

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    #6 berylrb, May 26, 2007
  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    <div class='quotetop'>QUOTE(TonyPSchaefer @ May 25 2007, 08:29 AM) [snapback]449719[/snapback]</div>
    What is your average trip distance?

    My experience has been that longer distances and higher speeds reduce the temperature penalty.

    Bob Wilson
     
    #7 bwilson4web, May 26, 2007
  8. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    <div class='quotetop'>QUOTE(donee @ May 26 2007, 08:36 AM) [snapback]450362[/snapback]</div>
    I'm not going to minimize the possibility of interconnected variables. I simply did not keep records on the dry-ness of each day and humidity and barometric pressure. There is one data point in particular in which there were something like 7 rainy days of the 11 for that tank. The mileage is bad for that temperature.

    <div class='quotetop'>QUOTE(berylrb @ May 26 2007, 11:35 AM) [snapback]450428[/snapback]</div>
    It occurred to me a couple years back that my chart would be much more accurate if I tracked mileage on a daily basis. Then reality/life/sanity hit me. So I decided to continue simply taking records when I refilled.

    <div class='quotetop'>QUOTE(bwilson4web @ May 26 2007, 10:47 PM) [snapback]450647[/snapback]</div>
    It seems true that on long distance trips at highway speeds, the impact of ambient temperature is reduced. I can see that when driving from the north side to the south side of Chicago. My average trip is 20 miles one-way to work, taking approximately one hour.
     
    #8 TonyPSchaefer, May 27, 2007
  9. FireEngineer

    FireEngineer Active Member

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    <div class='quotetop'>QUOTE(TonyPSchaefer @ May 26 2007, 11:56 PM) [snapback]450684[/snapback]</div>
    Wait!! You've been to the south side of Chicago, like south of Madison Ave., like south of US Cellular Field?
    I've seen no flares go up in the past couple of years :p .

    Wayne

    Who is currently relaxing in beautiful Estes Park, CO.
     
    #9 FireEngineer, May 27, 2007
  10. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    The South Side of Chicago. You know, South of Oakbrook.

    :p
     
    #10 TonyPSchaefer, May 28, 2007
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