|Re: WP-34s Demostration|
Message #21 Posted by Dieter on 18 Mar 2011, 12:27 p.m.,
in response to message #20 by Walter B
Hallo, Walter -
Addendum 1: Your observation concerning LOGy is correct. Point 2 on the bug list :-)
I assume you refer to the key label and the manual that have to be corrected. :-)
Addendum 2: Regarding the Gaussian distribution, the 21S is my handy benchmark (it just calculates the error probability, while we integrate from minus infinity as we were taught in math): According to my quick check, the results of the 21S are well equal to those of the 34s within |z| < 12. Personally, I don't care too much about probabilities below 1E-30, but YMMV.
Others do not care about angles between 89.9 and 90 degrees, or 12 to 16 places of Pi, but this certainly is no reason why incorrect results are acceptable. Look, this is a scientific calculator. In such a device, the least thing I expect are correct results over the whole working range. For daily use my 35s holds a normal distribution program that, of course, accepts p = 1E-499 and returns z = -47.8372821357. BTW within two seconds, which in some cases is faster than the emulator on a 1,8 GHz machine. ;-) Of course events with such a low probabilty virtually "do not happen at all", but that does not mean such values are meaningsless. A calculator is a "math tool", and it should give mathmatically correct answers. Not interpretations like "a very small number without practical meaning".
If the algorithm really is not able to handle values beyond |z| = 12 or p < 1E-40 it has to return an error message, and this restriction has to be documented in the manual.
But, honestly, I would expect the 34s to work like any other HP, TI, Casio, whatever calculator: simply return the correct answer. Am I asking for too much?