TechArena Community Generate some quality of random number via Random Number Generation function

# Generate some quality of random number via Random Number Generation function

## Windows Software

#1
13-01-2012
 Member Join Date: Jan 2012 Posts: 21
Generate some quality of random number via Random Number Generation function

For various ranges of "parameters", I routinely generate the same quantity of random numbers using the Data Analysis, Random Number Generation function ("uniform" distribution). Because I need to be be able to reproduce the random numbers, I choose a "Random Seed" number. My observations/questions are as follows. Are the random numbers returned for a certain seed number indeed random according to a uniform distribution? Are the "seed-related" random numbers any less random than random numbers returned without using a seed number? I ask because there appears to be a linear pattern with the first random number returned for seeds 1, 2, 3, 4, etc., for a specified range of parameters.

Is there a range of seed numbers that one must stay within when choosing random numbers from a specific range of parameters. For example, for parameters 1 to 1,000, must one choose a seed number from 1 to 1,000? In general, are there any guidelines/limitations inherent with Excel that I should keep in mind when assigning a seed number? Also, is there a "standard" random number generator that practicing scientists and engineers typically use other than Excel? Thanks for any assistance you can provide.

#2
13-01-2012
 Member Join Date: May 2011 Posts: 410
Re: Generate some quality of random number via Random Number Generation function

Random number generators produce pseudo random numbers. The numbers are not random as you have shown in that they are reproducible. Most random number generators use an algorithm that produces numbers between 0 and 1 inclusive from a uniform distribution. The generator produces a set sequence of numbers - so think of it as a fixed list of numbers. the list is finite. You might think of it as a circular list. then the seed determines where you enter the list in the circle (this is a calculation however; seed 2 does not start in the next number after seed 1). If the period of the list (number of entries) is too small, then you could get repeating numbers - you would start through the circle again. I would assume the Excel random number generator has passed statistical tests to show that it does a credible job of generating random numbers. I have seen it criticized here as not being particularly good (although concern would probably depend on what you are doing). I believe it was improved in excel 2003. As far as a standard, I don't believe such exists - I am sure there are many opinions on what is the best way. You should be able to find algorithms for generating random numbers on the web or in books such as numerical recipes in C.
#3
13-01-2012
 Member Join Date: May 2008 Posts: 38
Re: Generate some quality of random number via Random Number Generation function

Thank you for your reply and references to other articles.....will you please comment on the question I included in my original posting: Is there a range of seed numbers that one must stay within when choosing random numbers from a specific range of parameters. For example, for parameters 1 to 1,000, must one choose a seed number from 1 to 1,000?
#4
13-01-2012
 Member Join Date: May 2011 Posts: 446
Re: Generate some quality of random number via Random Number Generation function

There is a function like this which should do the trick : RANDBETWEEN = (1, 100). If not then the function you are talking about an add pascal76. You can add that from Tools > Add-Ins and check I do not know which one? But you can replace the function by = 1 + INT (RAND () * 100).
#5
13-01-2012
 Member Join Date: Jun 2011 Posts: 798
Re: Generate some quality of random number via Random Number Generation function

With the function = RAND (), with the = RANDBETWEEN, and Visual Basic language with the RND function, which is short for random. On the contrary, if we wish to generate a series of random numbers without repeating the task is a bit complicated because we must be carefully checked for each new number, if you are among those previously generated and if so disposable and generate another.