ENnies - let's launch the voting booth!

[Mathew_Freeman]

I voted for the few things I was aware of!

 

[Blacksway]

Well I've certainly been having fun with all the stats for the voting booth, although so far it hasn't made any difference to the actual winners and losers over a simple average so which system Russ will use I'm not sure.

One thing, Mr Olgar Shiverstone, I couldn't find an easy way of getting that nice percentage that you managed to produce. The function is in Excel but I wondered if there was a simple way to calculate it as I'm trying to keep the whole thing in PHP.

Ta.

(p.s. who let this get down to page 4, terrible!)

 

[Olgar Shiverstone]

One thing, Mr Olgar Shiverstone, I couldn't find an easy way of getting that nice percentage that you managed to produce. The function is in Excel but I wondered if there was a simple way to calculate it as I'm trying to keep the whole thing in PHP.

Does PHP have a function that calculates percentages of a standard normal?

Unfortunately, if PHP doesn't have a function that computes percentages as a function of a standard normal distribution, there really isn't an easy way to do it (which is why even in the computer age we still use Z-tables).

The function that returns the percentage is:

[Integrated from -infinity to X] (1 / SQRT(2 * pi)) * EXP (-1 * (x^2)/2)

So of course the integration is the problem. You could create a numerical integration function that stepped through the entire integration at very small intervals summing rectangles as an approximation, ie (translate this into PHP or whatever):

percent = 0
for i = -5 to x step 0.01
percent = percent + ((1 / SQRT(2* pi)) * exp (-1 * (i^2)/2)) * 0.01
next
percent=percent*100


Which should give a rough approximation (x is the normed value of the individual score ranging from -3 to +3). Smaller steps (change all 0.01 to 0.0001, for example) will yield a more precise value. I'm not sure exactly what method Excel uses to do this integration.

Edit: Forgot the square root of 2*pi

 

[jgbrowning]

quote deleted to prevent aditional sanity drain...

Agh!.... Stop the bad man! He's hurting me with his math!.....




joe b.

 

[Crothian]

Agh!.... Stop the bad man! He's hurting me with his math!.....




joe b.

I just want someone to explain what Normalised Score means and give some examples or something.