[R] New Sampling question

[Ista Zahn]

This can of course be done, but before I make any attempt to do it I
have to ask: why do you want this?

On Wed, Nov 17, 2010 at 7:08 PM, wangwallace <talenttree at gmail.com> wrote:
>
> I have another question about drawing samples from a data frame. This might
> sound really tricky. Let me use a data frame I have posted earlier as an
> example:
>
>    SubID    CSE1 CSE2 CSE3 CSE4 WSE1 WSE2 WSE3 WSE4
>      1          6      5       6       2      6      2        2       4
>      2          6      4       7       2      6      6        2       3
>      3          5      5       5       5      5      5        4       5
>      4          5      4       3       4      4      4        5       2
>      5          5      6       7       5      6      4        4       1
>      6          5      4       3       6      4      3        7       3
>      7          3      6       6       3      6      5        2       1
>      8          3      6       6       3      6      5        4       7
>
> this data frame have two sets of variables. each set simply represent one
> scale. as shown above, the first scale, say CSE, consists of four items:
> CSE1, CSE2, CSE3, and CSE4, whereas the second scale, say WSE, also has four
> items: WSE1, WSE2, WSE3, WSE4.
> the leftmost column lists the subjects' ID.
>
> I wanna create a new data frame through sampling random numbers from the
> data frame above. Below is the structure of the new data frame.
>
>    SubID    var    var   var     var
>      s          c      c      c       c
>      s          c      c      c       c
>      s          c      w     w       w
>      s          c      w     w       w
>      s          c      w     w       w
>      s          c      w     w       w
>      s          c      w     w       w
>      s          c      w     w       w
>
> in the new data frame:
>
> s= SubID range from 1 to 8
> var= variables
> c=CSE numbers
> w=WSE numbers
>
> some rules to construct the new data frame:
>
> 1. the top two rows have to be filled with CSE numbers; the numbers in the
> cells of each row should be randomized. for example, if the first row is an
> array of numbers from subject 4, they can follow the order: 4(CSE2),
> 5(CSE1), 3(CSE3), and 4(CSE4). Also, the numbers in the second row does not
> have to follow the order of the first row. for example, similarly, if the
> first row is an array of numbers from subject 4 in the order: 4(CSE2),
> 5(CSE1), 3(CSE3), and 4(CSE4), numbers in the second row (assuming it is
> from subject 8) does not have to be 6(CSE2), 3(CSE1), 6(CSE3), and 3(CSE4).
> numbers in these two rows should be drawn without replacement.
>
> 2. each of the rest of the rows should include a CSE number in the leftmost
> cell and three WSE numbers on the right. At the same time, in each row, the
> three WSE numbers on the right have to be only those numbers that are not
> corresponding to the CSE number in the leftmost cell. For example, if the
> CSE number in the leftmost cell is 4, a CSE2 number from subject 6, the
> three WSE numbers on the right side can only be 4(WSE1), 7(WSE3), and
> 3(WSE4) from subject 6.
>
> 3. the numbers in each row can only be drawn from the same subject. Also,
> Subjects should be randomized. Specifically, they does have to be in the
> following order:
>
>  SubID
>      1
>      2
>      3
>      4
>      5
>      6
>      7
>      8
>
> they can be:
>
>  SubID
>      2
>      8
>      5
>      4
>      1
>      6
>      7
>      3
>
> Any ideas?  Thanks in advance!! :)
> --
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> Sent from the R help mailing list archive at Nabble.com.
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org