My stats from the on-board trip computer:
4/22/16, 47 mph, 49 mpg, 334.3 mi
4/23/16, 44 mph, 50 mpg, 361.8 mi
4/24/16, 51 mph, 51 mpg, 304.1 mi
GPS Trip: 981.08
From
the gas and mileage record I get an average of 48.8 mpg. Here's the
interesting thing tho', when I calculate the mileage fillup by fillup,
the first two are 44.6 and 45.7 mpg; the remaining 5 average 49.6 mpg
with a std dev of 2.13. Yup, I did the t-test. Even with so few data,
the t-statistic is striking: -4.1 with a t-crit of 2.57 for 95%
probability. What does that mean? There is a better than 99%
probability that the data from the first 2 and last 5 are from two
statistically distinct populations. The first 2 are miles ridden using
fillups in PA: the previous Wawa fillup and the Sheetz fillup in
Carlisle; the remaining 5 are from fillups south of the M-D line. Guess
there's no question about ethanol in fuel in PA, huh?
