please provide a bit of the dataframe in the future using the dput() function
> x<-data.frame(height=1:10,
> color=sample(c("blue","green","brown"),10,replace=T))
> x
height color
1 1 blue
2 2 green
3 3 blue
4 4 brown
5 5 blue
6 6 brown
7 7 green
8 8 brown
9 9 green
10 10 brown
> blue.eyes <- x[x$color=="blue", ]
> blue.eyes
height color
1 1 blue
3 3 blue
5 5 blue
should create a new dataframe with only those that have blue eyes, then
> mean(blue.eyes$height)
[1] 3
should provide you with the mean of those.
On 31.10.2012, at 14:18, Hard Core wrote:
> I have a dataframe.
> Let's suppose that i have two columns. The first one contains height, the
> second one contains eye color that can be Green, Blue or Brown.
> I want to calculate the aritmetic mean of the height only for those people
> who have Blue eyes. How can I do it?
> Thank you for your availability.
>
>
>
>
> --
> View this message in context:
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>
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