The data have no resemblance to what prop.trend.test expects (counts and totals,
optionally group scores).
The prop.trend.test() function tests for trend in proportions. Were you
attempting a rank correlation, or maybe a rank sum (Wilcoxon type) test against
a directional alternative? (I'm not too sure, but package "coin"
might have the latter).
-pd
On 15 Jan 2014, at 07:30 , Keniajin Wambui <kiangati at gmail.com> wrote:
> I am using R3.02 on WIndows 7 64bit.
> How can I test for trend across ordered groups. I am using
> `prop.trend.test` but it doesn't order into groups and doesn't give
> the expected output of `sum of ranks` , `z value`...
>
> I have this data set and am doing
>
> `prop.trend.test (birthweight2$lbw2 ,birthweight2$gestwkgp2 )`
>
> Here is a sample data
> lbw2 gestwkgp
> normal birth weight 3
> normal birth weight 3
> normal birth weight 3
> normal birth weight 4
> normal birth weight 3
> normal birth weight 3
> normal birth weight 3
> normal birth weight 4
> low birth weight 2
> normal birth weight 4
>
>
>
>
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