Thanks for the feedback. Confirming your replies below: On Sun, Mar 30, 2014 at 4:59 PM, Raul Miller <[email protected]> wrote:
> > Sure you didn't mean for one of those to be distance driven? > > Yes, sorry, the columns are: Period, Car, Hours, Miles, Total Cost In this example, the car is logging trip start & end time (Hours). It's logging the # of miles driven. Let's assume the car is getting fueled up after each trip, so we know the cost. > Not to mention a 25% reduction in cars... > > Yes, I don't think the reduction in cars matters here though > I'd be tempted to set up a variety of simple models for cost, assume a > linear correlation and then use %. to see what kinds of numbers I get from > those. > Models might be: > > constant cost > linear cost based on speed > cost based on square of speed > cost based distance driven > cost based on mpg > This is somewhat similar to the path I was starting to go down. I'm not exactly sure how to make your suggestions actionable yet in terms of a model. If it's relatively simple to explain, I would be very interested (and others may be too). I was either going to: 1. Calculate the would-be cost by hold each variable constant. Example: calculate the cost if the the miles were the same and the speed were the same and then changing one at a time. 2. Calculate the impact by the ratio of each change -- assuming each are linear and on the same scale. 10% reduction in miles should be a 10% reduction in cost assuming MPH is held constant... Something like that I'll keep thinking and welcome all other ideas I have some crude code started here too that's using inverted tables: https://gist.github.com/joebo/fd61043076beafeace30 , just to make it more concrete ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
