[Lex Computer & Tech Group/LCTG] accuracy

[Robert Primak]

 Paul wins the Internet for today!
And yes, it is scientifically referred to as precision, not accuracy.
Nice catch, John! 

I wonder, could the extra "precision" be a result of converting from metric to English units? Failure to round would cause just such errors. 
With the help of a mis-programmed computer (or calculator), of course! (Or, an abacus, as almost all Amazon stuff these days comes from China?)
-- Bob Primak 

    On Sunday, September 20, 2020, 09:33:06 PM EDT, Paul Garmon <paul.garmon at gmail.com> wrote:  
 
 On Sun, Sep 20, 2020 at 4:47 PM john rudy <jjrudy1 at comcast.net> wrote:


I just purchased an item from Amazon.

Their accuracy is astounding. 

  



 
First off: Accuracy and Precision (so, precision is a closer match to just having more digits, as was already pointed out). Second
Maybe they were just using one of the old Pentiums, so it's wrong after a few decimal digits anyway?   ;->   
   - see: Pentium FDIV bug - Wikipedia   
   

   - How a Minor Calculation Error Cost Intel Half a Billion Dollars   
   
   
The presence of the bug can be checked manually by performing the following calculation in any application that uses native floating point numbers, including the Windows Calculator or Microsoft Excel in Windows 95/98.   
   

   
The correct value is:
      
         - {\displaystyle \textstyle {\frac {4,195,835}{3,145,727}}=1.333820449136241002}
   
   
When converted to the hexadecimal value used by the processor, 4,195,835 = 0x4005FB and 3,145,727 = 0x2FFFFF. The '5' in 0x4005FB triggers the fault in the FPU control logic. As a result, the value returned by a flawed Pentium processor in certain situations is incorrect at or beyond four digits:   [11]   [12]
      
         - {\displaystyle \textstyle {\frac {4,195,835}{3,145,727}}=1.333{\color {Red}{739068902037589}}}



This "package weight to the nth decimal digit" reminds me of something that happened a few years ago with Amazon shipping.  I had ordered an audio recording computer interface on a Wednesday morning, needed for that weekend. I specified ONE DAY DELIVERY and paid extra.  Figured it would be delivered either Thursday or (at worst) Friday, providing some time to set it up for Saturday. Well, when I checked on the delivery status early Thursday morning, Amazon reported the item was shipped UPS Ground with a TWO WEEK SHIPPING window.  Being critically important, I immediately ordered the same item from a place called SameDayMusic, for considerably more money (and that arrived on Friday, so the weekend was saved!). Meanwhile, I went to cancel the Amazon order, but they would not let me, since the item had not yet arrived. When the Amazon unit finally arrived the next week (ahead of their schedule), I went to return it, but they charged me for the ("no good reason") return, since it was delivered well within the time they said. I attempted to explain why it was late, but they kept saying "we see it arrived within the two weeks we allowed".  Saying that I had ordered it with one day delivery just didn't register with them, as it no longer showed on the order that way, so they didn't believe me. I figured it would never be resolved and I would just be out the return shipping (this was before I had Amazon Prime, so I think it was about $15). Well, a few weeks later, I noticed a news story saying that Amazon had formed a special executive group to deal with "things gone wrong" there, so I contacted them. Took a few weeks to investigate, but in this case, they figured out what happened, which was this: when an item would arrive in Amazon shipping, they would weigh it, and if it didn't match the weight listed in their database, they would change the shipping to ground instead of whatever had been specified (including overnight).  Probably, they should have just flagged the item in their database for review and shipped it as ordered, but that wasn't the procedure. They eventually refunded me the return shipping and also gave me a $50 gift certificate (and hopefully adjusted their shipping process).
Paul

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