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From |
Richard Williams <richardwilliams.ndu@gmail.com> |

To |
statalist@hsphsun2.harvard.edu, statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Adding randomness to a variable |

Date |
Mon, 21 Oct 2013 11:41:20 -0500 |

At 10:04 AM 10/21/2013, Owen Gallupe wrote:

Hi, Given the random number generator capabilities of Stata, I suspect there is an easy solution to this which I just haven't managed to track down. Having said that, is there any function that allows you to take an existing variable and add a small degree of randomness to it? I'm thinking along the lines of a jitter option when generating a variable. I know that this exact command doesn't actually exist, but a command of the following form is what I'm looking for: gen varx = jitter(var) My idea is that it would take this: 5 6 7 8 9 And turn it into something like this: 4.73 6.11 6.80 8.34 9.09 I'm aware that the following two options would produce something similar, but my idea is to manually create a variable that has the exact properties I want for teaching purposes but then add a little "error" to it. a) gen varx = .5*var1 + .8660254*var2 b) clear matrix c = (1.00, 0.30, -0.25, -0.10, 0.10, 0.20 \ /// 0.30, 1.00, -0.15, -0.10, 0.12, 0.35 \ /// -0.25, -0.15, 1.00, 0.13, -0.08, -0.16 \ /// -0.10, -0.10, 0.13, 1.00, 0.06, -0.14 \ /// 0.10, 0.12, -0.08, 0.06, 1.00, 0.001 \ /// 0.20, 0.35, -0.16, -0.14, 0.001, 1.00) corr2data var1 var2 var3 var4 var5 var6, n(2000) corr(c)

http://www3.nd.edu/~rwilliam/stats2/l21.pdf For existing data you can also do stuff like gen x2 = x + rnormal()

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**Follow-Ups**:**Re: st: Adding randomness to a variable***From:*Owen Gallupe <ogallupe@gmail.com>

**References**:**st: Adding randomness to a variable***From:*Owen Gallupe <ogallupe@gmail.com>

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