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    Re: A slope example
    From: Peter Fogg
    Date: 2010 Dec 4, 11:49 +1100

    George Huxtable writes (with venom dripping from his pen):
    Peter Fogg would have been better employed in getting his arithmetic right
    than in demonstrating his command of French.

    Actually, the French was to assist Antoine, who makes regular contributions in very good English, but apparently had difficulty on this occasion in grasping the point I was making.

    He doesn't provide units for the slope he has calculated of 57, but I will
    presume that this represents 57 arc-minutes over the 5 minutes of time
    covered by his plot. Is that correct?

    However, it's obvious to anyone's eye that the "calculated slope" and the
    "best fit" lines actually show a rotten fit to the plotted points, with
    insufficient slope. That appears to be because they have been plotted with
    a slope of 47 arc-minutes over the 5-minute period, not 57.

    Zut alors! (= Woops!)  Forgot the 30'.  Thank you for so sweetly pointing this out, George.

    And it's equally obvious to anyone's eye that the point he has pointed with
    an arrow as "averaged" cannot possibly be an average value of the 5 plotted
    points, in altitude and in time.

    Now I need to refer you to Antoine's posts.  The averaged value is his.  The discrepancy is what I was attempting to show.

    My own averaging of the 5 points given shows a mean time of 16h 30m 11.0
    seconds, not very far from his value. But I make the mean altitude to be
    69º 12.3', not his value of 69º 02.6'. and if you plot that point
    correctly, it then sits exactly where you would expect it to, in relation
    to the original 5 observations.

    Peter will have to do better

    Piterr will do better!  He will attempt a new, improved and hopefully better graph!  However, he doubts that it will make much difference to the outcome...
     
    if he wishes to persuade us to take his
    proposed method seriously, as an improvement on averaging.

    Now you can't be seriously proposing that my blunder is a fault of the technique, George?  That would be just silly.  We all make blunders, yourself not excluded.  Pompous suits you better, George.  Do your best to avoid silly.
     
    And preferably,
    next time, in English.

    Why "preferably", George?  I have to admire greatly all those who contribute to the NavList in English as a second or third language.  I know from experience how hard it can be to express oneself in another language.  We all benefit from their contributions in our native tongue, but why should I, or anyone else, not attempt to return that favour occasionally?

    Because you might fail to follow the narrative?  Well I have just one word to propose to you in respect of that, George, and here it is:

    http://www.microsofttranslator.com/
    http://translate.google.com/#auto
    http://au.babelfish.yahoo.com/

    Allright, 3-words.  Just in case you felt obliged to point that out in another blistering missive..



       
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