FAQ 7.31



2010/3/11 Lilia Leticia Ramírez Ramírez <llramirezramirez@gmail.com>

> Hello All,
>
> I would like to report the following bug or maybe you can explain if I am
> wrong.
>
> I am sampling from two different populations with weights. The two
> populations have the same age groups and I want to distinguish where I am
> sampling from. That is why I am using a matrix such as:
> matrix
> age.group      Male          Females       Weight.Males     Weight.Females
> 1               1.1                    1.2
> 3                                  4
> 2               2.1                    2.2
> 6                                   5
> 3               3.1                     3.2
> 3                                     5
> 4               4.1                     4.2
> 9                                  2
>
> If a sample a element:
> uno<-sample(matrix[,2:3],1,prob=matrix[,4:5])
> I want to be able to recover from wich age.group and sex the individual is,
> but
>
> as.integer((uno-round(uno))*10)  is equal to 0 when uno is male, while it
> is
> 2 when a female. That is, for example:
>
> as.integer((4.1-round(4.1))*10) is equal to 0 (instead of 1)
>
> The rounding error is eliminated for
> as.integer((uno[j,2]-round(uno))*11)  since it is equal to 1 when male and
> 2 when female.
>
> I noticed this problem when trying to use
>
> other.matrix[j, (uno[j,2]-round(uno))*10)]
>
> for a matrix with information with first information about males and second
> column about females.
>
> Thank you kindly.
> Lilia
>
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>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

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