Duh! Probability!

Duh! Probability!

Post by Stev » Fri, 14 Jul 2000 04:00:00



Evening all! I wonder if anyone can help me out with a problem. What I am
trying to do is to produce a set of numbers in Excel (97) using the random
number generator, but based around different probabilies, for instance, a
number between 0 and 7, but with a distribution chance of, say 0 = 10%, 1 =
25%, 2 = 25%, 3 = 15%, 4 = 10%, 5 = 5%, 6 = 5%, 7 = 5%. (I think that adds
up to 100%!). I'm not sure I've explained that too well, but if anyone can
understand what I'm trying to do, and can help, I'd be grateful to hear from
you.
Thanks, Steve S (remove spamless if replying).
 
 
 

Duh! Probability!

Post by Stev » Fri, 14 Jul 2000 04:00:00


Evening all! I wonder if anyone can help me out with a problem. What I am
trying to do is to produce a set of numbers in Excel (97) using the random
number generator, but based around different probabilies, for instance, a
number between 0 and 7, but with a distribution chance of, say 0 = 10%, 1 =
25%, 2 = 25%, 3 = 15%, 4 = 10%, 5 = 5%, 6 = 5%, 7 = 5%. (I think that adds
up to 100%!). I'm not sure I've explained that too well, but if anyone can
understand what I'm trying to do, and can help, I'd be grateful to hear from
you.
Thanks, Steve S (remove spamless if replying).

 
 
 

Duh! Probability!

Post by Stev » Fri, 14 Jul 2000 04:00:00


Sorry about the duplication - still getting to grips with this *y thing
at the moment!


Quote:> Evening all! I wonder if anyone can help me out with a problem. What I am
> trying to do is to produce a set of numbers in Excel (97) using the random
> number generator, but based around different probabilies, for instance, a
> number between 0 and 7, but with a distribution chance of, say 0 = 10%, 1
=
> 25%, 2 = 25%, 3 = 15%, 4 = 10%, 5 = 5%, 6 = 5%, 7 = 5%. (I think that adds
> up to 100%!). I'm not sure I've explained that too well, but if anyone can
> understand what I'm trying to do, and can help, I'd be grateful to hear
from
> you.
> Thanks, Steve S (remove spamless if replying).

 
 
 

Duh! Probability!

Post by Harlan Grov » Fri, 14 Jul 2000 04:00:00




Quote:>Evening all! I wonder if anyone can help me out with a problem. What I
>am trying to do is to produce a set of numbers in Excel (97) using the
>random number generator, but based around different probabilies, for
>instance, a number between 0 and 7, but with a distribution chance of,
>say 0 = 10%, 1 = 25%, 2 = 25%, 3 = 15%, 4 = 10%, 5 = 5%, 6 = 5%,
>7 = 5%. (I think that adds up to 100%!). I'm not sure I've explained
>that too well, but if anyone can understand what I'm trying to do, and
>can help, I'd be grateful to hear from you.

Since Excel's RAND function gives _uniform_ pseudorandom numbers,
create a table that pairs the numbers and their corresponding
cumulative probabilities, e.g., in A1:B8 enter

 0%  0
10%  1
35%  2
60%  3
75%  4
85%  5
90%  6
95%  7

then =LOOKUP(RAND(),A1:B8) should generate samples for your
distribution.

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