Al,

Say, your data file is 'test', execute the following in sequence,

aggregate(test[1],test[2],mean)->inter
names(inter)[2]='mean'
merge(test,inter,all=T)->inter2
inter2$RSV=inter2$Result/inter2$mean

The column 'RSV' in inter2 should be what you want.

Jun


On Tue, Mar 31, 2009 at 11:11 AM, Alan O'Loughlin <OLougA@wyeth.com> wrote:

>  Thanks for replying,
>
> Actually I was trying to give a simple example of calculations just to see
> the programming part of it. I'm actuually calculating the RSD% the 2 numbers
> are replica standard devation results... Here is an example of my data set.
>
>
>     Result Index
> 1   0.2901    17
> 2   0.2928    17
> 3   0.2913    18
> 4   0.2893    18
> 5   0.3526     9
> 6   0.3316     9
> 7   0.3492    10
> 8   0.3467    10
> 9   0.3385    11
> 10  0.3341    11
> 11  0.3449    12
> 12  0.3406    12
> 13  0.3690    13
> 14  0.3327    13
> 15  0.3324    14
> 16  0.3245    14
> 17  0.3245    15
> 18  0.3229    15
> 19  0.3331    16
> 20  0.3208    16
> Kind Regards,
> Al
>
> >>> Jun Shen <jun.shen.ut@gmail.com> 31-Mar-09 17:08 >>>
> Al,
>
> Is there any "ID" index for the pairs? For example, if the first pair can
> be labeled "a", and second pair labeled "b" etc., then you can add an index
> column or you may already have such a column in your list. Then run
> aggregate(your.data.column, by=index.column, FUN=mean). Or you can just add
> an extra index column anyway rep(1:number of the rows/2, each=2). Hope this
> helps.
>
> --
> Jun Shen PhD
> PK/PD Scientist
> BioPharma Services
> Millipore Corporation
> 15 Research Park Dr.
> St Charles, MO 63304
> Direct: 636-720-1589
>
> On Tue, Mar 31, 2009 at 10:40 AM, Alan O'Loughlin <OLougA@wyeth.com>wrote:
>
>> Hello,
>>
>> I'm trying to create a for loop for a data set, I have a list of results
>> in this data set and I want to take the 1st two add them together and divide
>> by the mean of the 1st to, then do the same for the 3rd and 4th values in
>> the list and so on and each time return a value for the calculation on each
>> pair.
>>
>> Any help would be appreciated.
>>
>> Thanks,
>> Al
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
>
>
>


-- 
Jun Shen PhD
PK/PD Scientist
BioPharma Services
Millipore Corporation
15 Research Park Dr.
St Charles, MO 63304
Direct: 636-720-1589

	[[alternative HTML version deleted]]


