Sharp Elsi Mate EL-8118 from the 70's in Japan: yet another VFD based calculator

[toml_12953]

(02-28-2015 02:41 PM)jebem Wrote:  

(02-28-2015 01:33 PM)rprosperi Wrote:  5/4 means "rounded off" - which is pretty ambiguous, since these same machines also had a "rounded down" and "rounded up" option.

Thank you, Bob.
Following your pointer, I did some testing.

Indeed, in this model, if the 5/4 selector is set to 4 decimal places, I get these answers:
1/3 = 0.3333 (5th decimal digit value below 5, so round down)
1/6 = 0.1667 (5th decimal digit value equal or above 5, so round up)

And this is what I have learn at the engineering technical school in the 70's, but we didn't call it 5/4, so I was not associating it with the rounding rules at all.

Statisticians do it differently. They round up if the last place desired is an odd number and down if an even (or some do it in reverse, down if odd, up if even) This way the cumulative errors tend to cancel each other out.

Round to two places example:

4.575 ==> 4.58 since 7 is odd, we round up
4.545 ==> 4.54 since 4 is even we round down