Thank you for reminding me.

######
food=c('fruit','fruit','fruit','drink','drink','drink')
type=c('apple','apple','orange','water','soda','soda')
value=c(2,3,1,5,7,6)
data=data.frame(food,type,value)
share=c((2+3)/(2+3+1),5/6,1/6,5/(5+7+6),13/18,13/18)
market_con=c(rep(0.8333333^2+0.1666667^2,3),rep(0.2777778^2+0.7222222^2,3))
data$market_con=market_con
######

Share= sum of value for specific type for some food / sum of value for all
types for some food

concentration= sum of square of share

For food 1, fruit, for apple ,there are two rows, value =2 and 3; for
oranget, value =1.

share_apple=(2+3)/(2+3+1)=5/6 ## It is the same for the two rows
share_organge=1/6

concentration_fruit= share_apple^2+sjare_orange^2=(5/6)^2+(1/6)^2

Hope this makes it easier to understand.

Thanks

Yi

On Wed, Aug 11, 2010 at 3:33 PM, Wu Gong <wg2f@mtmail.mtsu.edu> wrote:

>
> Hi Yi,
>
> It would be helpful for others to provide a solution if you give your
> formulas that calculating the value of share and concentration.
>
> ?apply will helps.
>
> Regards,
>
> Wu
>
>
>
> -----
> A R learner.
> --
> View this message in context:
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