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Re: 1/27 conference call notes; significant figures

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Fri, 6 Nov 2015 13:17:29 +0000

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 ```A very good question, Saašha. To look at it more generally, the question is, if a number is said to have _n_ significant figures, what do nonzero digits after the first _n_ mean, if anything? It seems like they should mean something! So, for example, 1920P2 should _not_ mean the same thing as 1950P2. But I don't recall ever seeing any discussion of this question. One reason is surely that an explicit statement of how many significant figures a value has is rare. You almost always have to infer the number of significant figures from the value itself. So we'd assume 1920 has three significant figures -- but if we're told it has only two, then what? --Don On Nov 6, 2015, at 6:40 AM, Saašha Metsärantala <[log in to unmask]> wrote: > Hello! > >> Saašha asks: "What would "1950P2" have as boundaries: (1900 and 1999) or (1950 and 2050)?" > >> 1900-1999. > >> Based on the example in the draft: "y17101e4p3 Some year between 171000000 and 171999999, estimated to be 171010000 ('p3' indicates a precision of 3 significant digits.)" > >> So '1950P2' means "a date estimated to be 1950, with two significant digits". > Thanks for this clarification. But then, What would "1900P2" have as boundaries: (1900 and 1999) or (1850 and 1950)? My point is: How much does the semantics of "P" overlap the semantics of "X"? Is 19XX a short form for 1950P2 or for 1900P2? Does 1920P2 mean the same thing as 1950P2 and 19XX? > > Regards! > > Saašha, --- Donald Byrd Woodrow Wilson Indiana Teaching Fellow Adjunct Associate Professor of Informatics Visiting Scientist, Research Technologies Indiana University Bloomington ```