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From: afe on 27 Jun 2010 05:25 On Jun 26, 5:58 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Surfer wrote: > > See: > >http://en.wikipedia.org/wiki/Tests_of_general_relativity#Perihelion_p... > > > Amount: arcsec/Julian century > > 5603.24 Total predicted > > 5599.7 Observed > > -3.54 Discrepancy > > > The discrepancy is larger than the observational error > > Before one knows whether or not this is significant, one must compare the > discrepancy to the errorbars. The above-referenced article does not do that, and > does not include the errorbars. > > So you must look up the errorbars in the literature before you can determine > whether this is important or not. insignificant, the entire science, including relativity, is based on patterns, not errorbars errorbars are barely significant to anything else, except from an engineering point of view good bye > > > In addition GR predicts that even a circular orbit with an > > eccentricity of zero would precess--but such precession would be > > unphysical. > > Not "unphysical", merely unmeasurable. > > Tom Roberts
From: afe on 27 Jun 2010 05:33 On Jun 26, 6:25 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Koobee Wublee wrote: > > On Jun 25, 8:58 pm, Tom Roberts wrote: > >> Before one knows whether or not this is significant, one must compare the > >> discrepancy to the errorbars. The above-referenced article does not do that, and > >> does not include the errorbars. > > >> So you must look up the errorbars in the literature before you can determine > >> whether this is important or not. > > > Not the errorbars again. > > Yes, OF COURSE "the errorbars again [sic]". Comparison between theory and > experiment (measurement) ALWAYS requires errorbars. untrue, only from an engineering point of view, in order to draw a fictive straight line in between the average of the extremities of a fictive errorbar diagram but the errorbar are it self subject to the 2nd order errorbar, who tells that the errorbars are the right answer, they are not embedded in any errorbar are infinitely many other errorbars, whereas all together result in useless errorbars diagrams good bye > > > What is the errorbar of the one due to other > > solar bodies? They seem to be very big, no? > > I do not know, and neither does the author of the post to which I responded, or > the author of the referenced article. THAT IS THE PROBLEM. Yes, I suspect there > are contributions to the errorbars on the measurement that are comparable to the > discrepancy. If, for instance, the errorbar turns out to be 3 arcsec/century, > then the claim "the discrepancy is larger than the observational error" is > correct, yet the discrepancy is not SIGNIFICANT, and thus is not important. > > For those of you who don't understand errorbars, let me explain. When making a > measurement, there is ALWAYS some experimental error [#]. So we model the > measurement process as yielding a distribution of values, with the actual value > as the mean of the distribution, and the sigma of the distribution being the > errorbar. It is observed that most measurement processes yield values that are > approximately Gaussian distributed, so this is usually a good model. The best > way to determine the errorbar is to measure it by taking multiple measurements > and determining mean and sigma from the different measurements. With that in > mind, only ~68% of the measurements will yield a value within one errorbar > (sigma) of the actual value, and ~5% of the time the value will exceed twice the > errorbar from the actual value. Assuming one has confidence in the value of the > errorbar, physicists generally consider a discrepancy of 2 sigma or less to be > not significant, a discrepancy between 3 and 4 sigma as inconclusive but > provocative, and a discrepancy of 5 sigma or more as pretty definitive. > > [#] Error in the sense of discrepancy from the actual value, > not in the sense of "mistake". This is standard usage. > > That said, I would not consider this discrepancy of 3.54 arcsec/century to be a > problem unless the errorbar on the measurement is smaller than about 0.7 > arcsec/century. If it's less than about 1.2 arcsec/century then it's probably > worth revisiting. > > [Astronomers know this, and the fact that they are not revisiting > this makes me infer that it is not a problem. But new techniques > can often reduce the errorbar, and that can make it worth re-doing.] > > Tom Roberts
From: J. Clarke on 27 Jun 2010 06:49 On 6/27/2010 5:33 AM, afe wrote: > On Jun 26, 6:25 pm, Tom Roberts<tjroberts...(a)sbcglobal.net> wrote: >> Koobee Wublee wrote: >>> On Jun 25, 8:58 pm, Tom Roberts wrote: >>>> Before one knows whether or not this is significant, one must compare the >>>> discrepancy to the errorbars. The above-referenced article does not do that, and >>>> does not include the errorbars. >> >>>> So you must look up the errorbars in the literature before you can determine >>>> whether this is important or not. >> >>> Not the errorbars again. >> >> Yes, OF COURSE "the errorbars again [sic]". Comparison between theory and >> experiment (measurement) ALWAYS requires errorbars. > > untrue, only from an engineering point of view, in > order to draw a fictive straight line in between the > average of the extremities of a fictive errorbar diagram > > but the errorbar are it self subject to the 2nd order > errorbar, who tells that the errorbars are the right > answer, they are not > > embedded in any errorbar are infinitely many other > errorbars, whereas all together result in useless > errorbars diagrams Take a statistics^H^H^H^H^H^H^H^H^H^H class. You have no idea how error bars work or what their utility is.
From: tue on 27 Jun 2010 07:41 On Jun 27, 12:49 pm, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > On 6/27/2010 5:33 AM, afe wrote: > > > > > On Jun 26, 6:25 pm, Tom Roberts<tjroberts...(a)sbcglobal.net> wrote: > >> Koobee Wublee wrote: > >>> On Jun 25, 8:58 pm, Tom Roberts wrote: > >>>> Before one knows whether or not this is significant, one must compare the > >>>> discrepancy to the errorbars. The above-referenced article does not do that, and > >>>> does not include the errorbars. > > >>>> So you must look up the errorbars in the literature before you can determine > >>>> whether this is important or not. > > >>> Not the errorbars again. > > >> Yes, OF COURSE "the errorbars again [sic]". Comparison between theory and > >> experiment (measurement) ALWAYS requires errorbars. > > > untrue, only from an engineering point of view, in > > order to draw a fictive straight line in between the > > average of the extremities of a fictive errorbar diagram > > > but the errorbar are it self subject to the 2nd order > > errorbar, who tells that the errorbars are the right > > answer, they are not > > > embedded in any errorbar are infinitely many other > > errorbars, whereas all together result in useless > > errorbars diagrams > > Take a statistics^H^H^H^H^H^H^H^H^H^H class. You have no idea how error > bars work or what their utility is. that would be stoopid, empirical data has nothing to do with statistics statistics is what you use when you do dirty tricks and tell lies to people better you take a kindergaarten class in Numerical Analysis, this is must when you deal with sets fo empirical data now go tell your lies other places good bye
From: Henry Wilson DSc on 27 Jun 2010 18:03
On Sat, 26 Jun 2010 03:55:47 +0930, Surfer <no(a)spam.net> wrote: >See: >http://en.wikipedia.org/wiki/Tests_of_general_relativity#Perihelion_precession_of_Mercury > >Amount: arcsec/Julian century > >5603.24 Total predicted >5599.7 Observed > >-3.54 Discrepancy > >The discrepancy is larger than the observational error > >In addition GR predicts that even a circular orbit with an >eccentricity of zero would precess--but such precession would be >unphysical. Orbit precession is significantly influenced by the finite speed of gravity. Henry Wilson... ........Einstein's Relativity...The religion that worships negative space. |