Random Number

[Chris Davison]

Evening all,

how can I return a single random number from the set : 1 to 10 and 20 to 30

ie

8 would be okay
2 would be okay
23 would be okay
29 would be okay

but 15 would not be okay
and 18 would not be okay

Just one random number from those ranges 1-10, 20-30

I'm pretty familiar with =RAND and also have the Analysis Toolpak installed

many thanks
Chris

 

[eliW]

Eli,

Your first formula (slightly modified here) appears to me elegant and satisficing:

=IF(RANDBETWEEN(0,1),RANDBETWEEN(1,10),RANDBETWEEN(20,30))

The size of <1,10> is eq to that <20,30>. Is there something I'm missing?

Regards,

Aladin

Hi Aladin,
1-10 contains 10 numbers, 10-20 contains 11 numbers, therefore the randomal numbers which is formed by the first formula would be biased so that there will be statistically slightly more numbers between 1-10 than between 20-30.
Do I make myself clear?
Therfore the second suggestiom is making compensation of that.
The exact formula would be:
=if(randbetween(1,21)<=10,randbetween(1,10),randbetween(20,30))
Regards,
Eli

 

[Aladin Akyurek]

On 2002-03-31 09:05, eliW wrote:

Eli,

Your first formula (slightly modified here) appears to me elegant and satisficing:

=IF(RANDBETWEEN(0,1),RANDBETWEEN(1,10),RANDBETWEEN(20,30))

The size of <1,10> is eq to that <20,30>. Is there something I'm missing?

Regards,

Aladin

Hi Aladin,
1-10 contains 10 numbers, 10-20 contains 11 numbers, therefore the randomal numbers which is formed by the first formula would be biased so that there will be statistically slightly more numbers between 1-10 than between 20-30.
Do I make myself clear?
Therfore the second suggestiom is making compensation of that.
The exact formula would be:
=if(randbetween(1,21)<=10,randbetween(1,10),randbetween(20,30))
Regards,
Eli

I was aware of the reason. I thought: "The sizes of intervals are eq -- what is he worried about?" Gee, back to the elementary for me .

 

[Jack in the UK]

Hi Aladin..

No just us exceller being difficult AS ALWAYS..

you formua is PERFECTION.. but this is a case of...

6 differen number in one cell, no two the same..

Kinda tough.. Any ideas mate!