Help with Excel

• rainee

  5 Oct 05, 12:43

  I need help urgently...I have this assignment which is due tomorrow, where I have to generate a list of random points based on a standard deviation/variance that I have calculated from some data. Anyone knows how I can do that using Excel? Any help is appreciated...
• ditzy

  5 Oct 05, 12:50

  Tools>Add-ins>Analysis Toolpak>OK
  
  Tools>Data Analysis>Random Number Generation
  
  
• rainee

  5 Oct 05, 12:55

  Originally posted by ditzy:

  Tools>Add-ins>Analysis Toolpak>OK
  
  Tools>Data Analysis>Random Number Generation
  
  

  But that one will allow me to put in standard deviation? or variance?
  
  I searched HELP in Excel and I got a function NORMINV that will allow us to put in variables, mean and standard deviation, but I dun need the mean to be there...just want standard deviation...
• rainee

  5 Oct 05, 12:56

  ok, I think random number generator in Tool Add-ins allow me to do the same thing...but I still dun wan to insert Mean...
• rainee

  5 Oct 05, 13:26

  Now need help again *sigh* I am really bad with Excel, but no choice but to use it for this class
  
  Anyway, I am supposed to calculate this..
  
  A(t) = a + b*A(t-1) + u(t)
  
  a and b are constants I have, and I got u(t) thru the random generator thing.
  
  So now the problem is I have to generate this 50 times. I only have the first
  A(t-1) and for the other 49 times, I need to get A(t-1) from the previous A(t)...Like let's say
  
  A(2) = 54
  A(3) = a + b*54 + u(3)
  
  So is there an easier way to do this automatically 50 times w/o having to put in A(t-1) everytime?
  
  Pls do help...Thanks..
• the.raven

  5 Oct 05, 13:31

  Originally posted by rainee:

  Now need help again *sigh* I am really bad with Excel, but no choice but to use it for this class
  
  Anyway, I am supposed to calculate this..
  
  A(t) = a + b*A(t-1) + u(t)
  
  a and b are constants I have, and I got u(t) thru the random generator thing.
  
  So now the problem is I have to generate this 50 times. I only have the first
  A(t-1) and for the other 49 times, I need to get A(t-1) from the previous A(t)...Like let's say
  
  A(2) = 54
  A(3) = a + b*54 + u(3)
  
  So is there an easier way to do this automatically 50 times w/o having to put in A(t-1) everytime?
  
  Pls do help...Thanks..

  I dunno how to use excel but I think you can write a recursive equation for an entire column?
• launtpc

  5 Oct 05, 15:52

  (first ever post in 3 days that does not have message boxes)
  
  OK... this is much easier in Visual Basic (Microsoft Office sure has VBA, or Visual Basic for Applications). Make a macro
  
  The use the rnd command for random number...
  
  Easier than excel's sh!tty forumulas, trust me. (provided you know VB of course)