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Started by Figleaf, February 03, 2013, 03:30:09 PM
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Quoteshowing two versions side by side on the forum can be very instructive
Quote from: GSDykes on September 24, 2015, 08:17:45 AMHere is a link (below) to view and print a free PDF file which I made. It is a handy chart of various coin alloys and their specific gravities. It also shows the S.G. of common elements as well as information on alloyed silver (Ag) coins. It is free to view, read, download and print (landscape format). Enjoy. Share.www.Biblical-data.org/GSDykes_Specific_gravity_tests.pdfGary in Washington
Quote from: Figleaf on February 03, 2013, 03:30:09 PMObserved coin weights are imprecise, because of wear and dirt.
Quote from: Figleaf on February 03, 2013, 03:30:09 PMThe best way to divine the official weight is to have 1000 copies, weigh them, determine average and standard deviation (Excel will do this for you.)
Quote from: EWC on September 25, 2015, 09:44:09 AMIn a paper on the weight of Charlemagne's pennies Miskimin assumed every known specimen was 10% low due to "leaching in the ground" or some such. That is rubbish. Many coins come from the ground exactly as the went into it
Quote from: EWC on September 25, 2015, 09:44:09 AMI think there are circumstances where standard deviation should be avoided. It assumes distributions will be near normal, and can mislead badly where they are not. It troubles me that almost the entire education system has ignored this problem for a whole century now.
Quote from: Figleaf on September 25, 2015, 08:41:45 PM If the Charlemagne coins were found all over Western Europe, and the coins are of reasonably good quality (say 80% silver, 20% copper), a 10% average would seem about right.
Quote from: Figleaf on September 25, 2015, 08:43:59 PMWhy would the distribution not be (near) normal?
Quote from: Figleaf on September 27, 2015, 08:40:16 PM The skewedness of a graph can be spotted on sight.