Random Numbers

[lou]

I tried to search through all the postings on the board to see if
somebody already has answered my question but I couldn't seem to find
it.

I was trying to help somebody in my audit department generate a list
of random number from a spreadsheet of Work Orders they have. They
want the random numbers to be generated from the list but favor the
higher cost items.

So I have 2 columns WO# and Cost. I used the random number generator
and set it on discrete but some numbers got duplicated. I added
another column to create a % that the cost makes up of the total cost
to I guess give it a higher probability. I'm not a statistics person
so I don't know if I'm completely messsing up the data.

With the situation I have above with the 2 columns of WO# and Cost.
How would I go about creating a list that does not have any duplicate
numbers in it and favors the Work Orders that are bigger ticket items?

Thanks

 

[Gary''s Student]

Use separate buckets.

THE USUAL CASE:

say we have 100 items and want to pick 10 at random:
1. put the items in column A
2. put =rand() in column B
3. sort both columns by column B
4. grab the top 10 items

This will randomly select 10 out of the 100.

THE WEIGHTED CASE:
1. Put the most expensive 30 items in column A and the least 70 in column H.
2. Scramble both lists as above.
3. Grab the top 5 items from A and also from B

This is still a random sample, but it favors the expensive items.