[R] Glitch in Kruskal-Wallis test?

[Jenny Liu]

Hi Michael,

Thank you for your reply! I'm testing the difference in proportions. Temp
is temperature, and Prop is the proportion of insect pupae that survived at
that temperature. I was told by a statistician that the K-W was appropriate
for testing proportions, but perhaps you know of an alternative? I have
already tested for heteroscedasticity using the Breusch-Pagan test.

Thanks again,
Jenny



On Dec 22, 2018 7:38 AM, "Michael Dewey" <lists using dewey.myzen.co.uk> wrote:

Dear Jenny

What exactly do you think you are testing here? You are telling K-W you
have seven groups each with a single value which is not the usual
situation for K-W.

Michael


On 22/12/2018 04:58, Jenny Liu wrote:
> Hi everyone,
> I have been running a K-W test with the attached data, PupMort1. My code:
> kruskal.test(Prop~Temp,data=PupMort1)
> However, I found that I get the exact same result when I change the
x-values, as
> in the attached data PupMort2.
> Test run with PupMort1Kruskal-Wallis rank sum testdata:  Prop by Temp

> Kruskal-Wallis chi-squared = 6, df = 6, p-value = 0.4232
> Test run with PupMort2Kruskal-Wallis rank sum testdata:  Prop by Temp

> Kruskal-Wallis chi-squared = 6, df = 6, p-value = 0.4232
> Does anybody know why this is happening?
> Thank you!
> Jenny
>
>
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-- 
Michael
http://www.dewey.myzen.co.uk/home.html

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