Sorry for not being more explicit in my emails, the code I am using was not
generated by me therefore I was not in the position to share it.
Sorry if the information i have provided is insufficient or if I have wasted
peoples time.
Basically I have the information listed below I.e n and the quantiles of the
random distribution and was wondering if a mean could be calculated from this
or if I needed to modify the code to output the mean?
the next columns are quantiles of the randomised PD distribution for
significance testing
#the probabilities are given as column names and are designed to
allow 1- and 2-tailed
#testing at the 0.05,0.01 and 0.001 levels, plus a spread at 0.1
intervals across the range.
Sent from my iPhone
On 29 Jan 2011, at 21:48, David Winsemius wrote:
>
> On Jan 29, 2011, at 9:39 AM, Peter Francis wrote:
>
>> Dear all,
>>
>> The data is generated from 1000 random samples of a phylogenetic tree to
>> calculate phylogenetic diversity. I sampled the tree 1000 times at with
>> various species communities (600) to get a random PD per community. I then
>> want to test my observed PD with that of a random sample to test for
>> significance.
>
> Color me puzzled. I thought you already had a test (the p value) and you
> wanted an estimate for a mean given that you had a 95% CI.
>
>> However the script i used, output
>>
>> q0.005q0.01 etc upto q0.995
>
> Those look like names or labels for quantiles. This would move along a lot
> faster if you gave a more complete listing of the output and the code used to
> generate it.
>
> --
> David.
>>
>> But i wanted to know the mean PD value per community based on the output,
>> and that is where i am struggling
>>
>> Thanks,
>>
>> Peter
>> On 29 Jan 2011, at 02:16, Joshua Wiley wrote:
>>
>> Hi Peter,
>>
>> Do you know the formula used to calculate the confidence interval? I
>> suspect it is possible with minimal algebraic manipulation of the CI
>> formula to find what the mean is. Assuming a normal distribution (as
>> David), then it is certainly possible to find. This wikipedia page
>> might help:
>>
>> http://en.wikipedia.org/wiki/Confidence_interval
>>
>> And no, this is not really the correct place to ask. My basic rule of
>> thumb is, "Does my question have anything to do with R? If my answer
>> is, "No." then I usually look for somewhere else to post. Of course,
>> for a comprehensive list, see the posting guide.
>>
>> If you are wondering if there is a function to do it for you, I am not
>> sure, but it would be trivial to programme and if you show us the
>> formula for it (the mean from the CI), we can certainly give you
>> pointers for how to write your own :)
>>
>> Cheers,
>>
>> Josh
>>
>> On Fri, Jan 28, 2011 at 2:15 PM, Peter Francis wrote:
>>> Dear List,
>>>
>>> I am not sure if A) this is possible or B) the correct place to ask.
>>>
>>> I am looking to find the mean - i have n, and the two-tailed confidence
>>> intervals 0.95 & 0.25 with a p-value of 0.05.
>>>
>>> Can i find the mean from this data ?
>>>
>>> Thanks
>>>
>>> Peter
>
> David Winsemius, MD
> West Hartford, CT
>
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