Teal, If I was on TV, I would play two (to U), if you know what I mean. What you said triggers a few neurons re this subject from my student days. You are no doubt correct.
Not all lies and damned statistics, but smoke and mirrors have their place too! Which brings us to magic. Arthur C Clarke has already been quoted on this subject, on this forum, but here is his quote again: "Any sufficiently advanced technology is indistinguishable from magic." Hand up those that know the name Henry K Millicer. If not, you can look up his details on the web. In the early seventies Henry suggested that a 50:1 glider was possible. [A genuine 38:1 was considered to be about as good as it gets in those days.] Was he mad? Was he a visionary? Well time has shown us that he was not mad. Was he a visionary? Possibly, but more to the point as a good engineer, he was able to extrapolate from the known to the unknown. The Perlan project is certainly a topical project that intends to venture into the unknown. With Airbus Group sponsorship/backing, the project is now likely to happen, and it will be fascinating to see what eventuates. Since Airbus came on board, the spin doctors have been at work, and I wryly note that that the possibility of flying around in the Martian atmosphere is now being linked to the project. The Spin doctors will need to pick up their act to exceed the imagination of Edgar Rice Burroughs, when it comes to things Martian. Regards, Gary -----Original Message----- From: Aus-soaring [mailto:[email protected]] On Behalf Of Teal Sent: Thursday, 10 March 2016 5:50 PM To: Discussion of issues relating to Soaring in Australia. Subject: Re: [Aus-soaring] Comparing accident rates On 10/03/2016 5:05 PM, Texler, Michael wrote: > It is always difficult to compare accidents rates for 'rare' events due to the wide 95% confidence intervals. > http://www.evanmiller.org/ab-testing/poisson-means.html > > As mentioned by others, there often needs to be an order of magnitude difference (i.e. a 10 tenfold increase or decrease of an accident rate) to demonstrate statistical significance at the 95% level (this also means that there is a 5% chance of accepting a chance variation as being significant). Not actually true; the degree of difference between groups/cases/whatever that you'll need to to get a statistically significant result (be it for p=.05 or p=.01 or whatever) will depend on the sample size, and on the characteristics of the sample and the population you're drawing the sample from. There is in fact a whole sub-topic of stats that is about working out what size sample you need for a given situation in order to be able to plausibly see any real differences between groups, should there be a real difference to be found. > It is not lies and damned statistics, but a 5% chance that the result is in error (using commonly accepted practice). > > See: > https://en.wikipedia.org/wiki/Poisson_distribution > > Comments from statisticians welcome. I'm an experimental psychologist - not an actual full-time statistician, but I do play one on TV (if you know what I mean). Teal _______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2016.0.7442 / Virus Database: 4540/11782 - Release Date: 03/09/16 _______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring
