On Aug 6, 2012, at 7:41 PM, Allan in Portland <allan_f...@aracnet.com> wrote:
> > > On Monday, August 6, 2012 5:16:03 PM UTC-7, z-man wrote: > You're not going to determine what rolls faster by rolling down a hill and > measuring with a stop watch. > > Um, why not? Assuming one is rigorous with the measuring, ie. calm wind, > repeat roll-downs, same bike & rider, etc. Have you read the test procedure > they used? Seemed solid to me, which is why I'm asking. Thx. While Jan et al made a lot of efforts to minimize the variables- the goal of experimental design being to eliminate all fariables except the one you want to measure- doing a coast down ride with a live human on board, outside, etc., has too many variables that may intrude. They worked hard but the design of the experiment doomed it to having too much noise, even with careful statistical analysis, to produce reliable and valid results. I have much preferred the tests Jan has done using a power meter, which also has uncontrolled variables but seems to me to be a more direct way to measure the feature of interest: how efficient the bike is with product A vs. product B. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
