R help - Oct 2011 - Significance of trend

Hi everyone,

I'm trying to determine the significance of a trendline. From my internet
search months ago, I came across the following post. I modified tim and
dat for simiplicity.

tim <- 1:10
dat <- c(0.17, 1.09 ,0.11, 0.82, 0.23, 0.38 ,2.47 ,0.41 ,0.75, 1.44)

fstat <- summary(lm(dat~tim))$fstatistic
p.val <-
1-pf(fstat["value"],fstat["numdf"],fstat["dendf"])

The resultant p.value is 0.261. But I want to know if this
value is significant and at what significance level. How do I check for
it?

Thanks

-- 
Muhammad

I'm thinking you need to read up on what a p-value is:
https://secure.wikimedia.org/wikipedia/en/wiki/P-value

Michael Weylandt

On Mon, Oct 31, 2011 at 2:51 PM, Muhammad Rahiz
<muhammad.rahiz at ouce.ox.ac.uk> wrote:
> Hi everyone,
>
> I'm trying to determine the significance of a trendline. From my
internet
> search months ago, I came across the following post. I modified tim and
> dat for simiplicity.
>
> tim <- 1:10
> dat <- c(0.17, 1.09 ,0.11, 0.82, 0.23, 0.38 ,2.47 ,0.41 ,0.75, 1.44)
>
> fstat <- summary(lm(dat~tim))$fstatistic
> p.val <-
1-pf(fstat["value"],fstat["numdf"],fstat["dendf"])
>
> The resultant p.value is 0.261. But I want to know if this
> value is significant and at what significance level. How do I check for
> it?
>
> Thanks
>
> --
> Muhammad
>
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