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GEOSTATS: The controlled experiment

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  • DrPaulREarl
    Geostat people: Everybody wants to prove something, yet mighty few will give the reader the error terms he needs to judge the evidence. A few journals even say
    Message 1 of 1 , Feb 15 11:27 AM
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      Geostat people:
      Everybody wants to prove something, yet
      mighty few will give the reader the error terms he needs
      to judge the evidence. A few journals even say just slip
      in "p = 0.95"; do NOT give the ANOVA.
      Well in the recent dolphin case, it is not the
      application of a test of randomness as the observations
      are ordered, etc. The matter is acquiring an experi-
      mental attitude that involves randomization and repli-
      cation. The control is something known sometimes, and
      the experimental something to be defined. This much can
      be a long hard path for a beginner or an expert. Sampling
      size demands may be way beyond our capacities, yet we
      assume consecutive samples are reasonably smaller than
      genuinely independent ones. Words like independent and
      normal are historic and convenient, not rigorous. The
      thing being measured is the response variable, and the
      controls are the independent variables by convention.
      The shorter the interval, the better... more
      points, less variance and higher cost. However, it may
      be mendacious to connect dolphin sightings as each can
      be a different one. We might need a tag-and-release
      system for a population as in PAP Moran (1951, Biometri-
      ka). The rub is that while these things are simple,
      they are costly.
      "Random" often covers unknown assignable causes.
      If we get a coefficient of determination of r squared =
      0.85, and then we correlate some other variable to find
      0.92, we are making real progress. Might we find another
      variable and reach 0.97? We would take that as a lawlike
      relation and would put that 0.03 down to random
      fluctuation.
      Much of use is under Quality Control. Despite
      the Genichi Taguchi effect, Experimental Designs by WG
      Cochran & GM Cox (1957) and Planning Experiments by DR
      Cox (1958) remain good books as they can form attitude
      thus intuitive level.
      Two other books are GEP Box & GM Jenkins (1970)
      and GM Jenkins & DG Watts (1968) that deal with time
      series. These 4 books are in the Fisher-von Mise-Feller
      class.
      Dolphins can be forecasted. Monitoring programs
      justly popular in biology are available off the net.
      Still, they surely require massive inprovement.
      We want a high number of observations taken at
      uniform distances especially if we translate time to
      distance. If a ship has uniform speed, and we have its
      direction, we know where it will be after a given time.
      Nonetheless, dolphin activity is cyclic. The same
      dolphin is both coastal and far oceanic. Autocorrelation
      and crosscorrelation with a control should provide
      interesting results.
      However, the sighting alone without the ecological
      oceanic parameters associated is not playing the game.
      This is the missing set of assignable variables. No
      investigations on fluctuations in the sizes of dolphin
      populations are worth the powder to blow them to Hell.

      Part of that is from confusing random
      with determined effects. Part is by
      mendacity.

      We do have an empty set, so face up to it.

      So she says, "Don´t you understand that if
      I don´t have positive findings, my funding
      will be cut off?" Or, "How can I defend my
      thesis?"

      Next, we have about 3 species like spotted
      to worry about. Even with 20/20 vision,
      the observer has only a foggy notion of
      which species she saw.

      Getting a dolphin-beamed radio signal (tag)
      certainly will make data so that one has to have online
      computer interfacing. (Ask the Bell Laboratories.) The
      opposition is using tuna-beamed signals and has found
      the S/N ratio intolerable.

      Best, Paul

      PS Do you remember who said, "You can fool some of the
      people some of the time, but you can´t fool all of the
      people all of the time." ?

      PPS As the dolphinic student inappropriately requested a
      test for if-it-were-random, this quote is added from Box
      & Jenkins.

      "Much of statistical methodology is concerned with models
      in which the observations are assumed to vary indepen-
      dently. In many applications, dependence between the
      observations is regarded as a nuisance, and in planned
      experiments, randomization of the experimental design is
      introduced to validate analysis conducted as if the
      observations were independent. However, a great deal of
      data in business, economics, engineering and the natural
      sciences occurs in the form of time series where ob-
      servations are dependent and where the nature of this
      dependence is of interest itself."

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