The completely unscientific, unsubstantiated gas octane experiment

I'm conducting my own little research in relation to my car and gas mileage.  My sister reminds me on a semi-regular basis what a geek I am when it comes to gas prices.  Usually the conversations go something like this:

"I've got to stop and get some gas...oh, here's a station." -Laura, as she pays no attention to what price gas is anywhere.

"I got gas for $___ a gallon in (insert random town) the other day.  If you've got enough in your tank you could make it to (insert station name) and save a few cents a gallon."  -Lisa

"Why do you notice the gas prices everywhere you go??  You're being so Eulas right now." -Laura  (Eulas [sounds like yew-less] is my grandfather & my dad's first name.  My dad does NOT go by this name, he goes by his more normal middle name, but my siblings and I use it at times to refer to particular actions that seem somewhat...ummm, geeky, frugal, and/or odd when it comes to sense of humor. Such as "You pulled a eulas." ;-)

So, I laughed at myself a little bit the other day when I decided to fill my car with premium gas (not "required" for my car) and reset my odometer to calculate the mileage.  I reset it yesterday when I filled up with regular gas.  I'm trying out a theory on octane levels and gas mileage in my car.  It is based on absolutely no fact or research...just to satisfy my own mind.

Come on, gas won't be this cheap forever...I'm just curious if there's a difference.  

(Don't get the wrong idea...I'm not the budgeted penny pincher I should be when it comes to other stuff.  Why I chose the cost of gas per gallon to notice every time I pass a gas station but don't seem to have a problem with the cost of make-up, I don't know. :-)