Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Experiment: coast down distances (rolling resistance) @ various tire pressures

LioNiNoiL · 04-14-2013, 03:03 AM

psi feet

20 568
20 570
30 662
30 672
40 677
40 679
50 667
50 679
60 681
60 692

The same type of analysis of these earlier data is a bit more interesting than the previous analysis, because of the high SRC (+0.8944) between 60psi and 50psi, which has low significance (at 0.167 level) due to small sample size of only four pairs of data.
Including the 40psi data reduces the SRC to +0.667 with greater significance (at 0.074 level) because of more data.
Including the 30psi data increases the SRC to +0.761 significant at 0.014 level.
Including the 20psi data further increases the SRC to +0.877 highly significant at 0.0004 level.
In these data, it appears that increasing pressure to 60psi may result in an increase in feet (unlike the previous data) but the significance is low enough to diminish our confidence in this result. As is stated nearly always in such cases, we need more data.

04-14-2013, 03:03 AM	#103 (permalink)
LioNiNoiL EcoModding Wannabee Join Date: Sep 2011 Location: fabulous Las Vegas Posts: 14 Thanks: 6 Thanked 7 Times in 5 Posts	more data analysis psi feet 20 568 20 570 30 662 30 672 40 677 40 679 50 667 50 679 60 681 60 692 The same type of analysis of these earlier data is a bit more interesting than the previous analysis, because of the high SRC (+0.8944) between 60psi and 50psi, which has low significance (at 0.167 level) due to small sample size of only four pairs of data. Including the 40psi data reduces the SRC to +0.667 with greater significance (at 0.074 level) because of more data. Including the 30psi data increases the SRC to +0.761 significant at 0.014 level. Including the 20psi data further increases the SRC to +0.877 highly significant at 0.0004 level. In these data, it appears that increasing pressure to 60psi may result in an increase in feet (unlike the previous data) but the significance is low enough to diminish our confidence in this result. As is stated nearly always in such cases, we need more data. __________________ "There's no tellin' where the money went" -- Robert Palmer, "Simply Irresistible" (1988)