Hi Matthew,
Yep, that’s what I thought as well - just wanted to be sure!
Cheers,
Donal
> On 29 Mar 2016, at 16:11, Matthew Webster <[log in to unmask]> wrote:
>
> Hi Donal,
> The 0 entries are fully part of the null-distribution, as a trivial example, if only the unpermuted statistics displayed non-zero sized clusters, and _all_ the permutated stats had zero clusters, then it is very likely the clusters in the unpermuted case are significant.
>
> Kind Regards
> Matthew
>> Hi Matthew,
>>
>> I have another question regarding the text file output of maximum cluster size. Very many of the values are zero, which I guess occurs when you permute and find no cluster.
>>
>> Should I consider the zero values as part of the nut distribution I form, or should I build the null distribution only from the non-zero clusters found? This will obviously change the position of the 95th percentile, so just thought I’d check!
>>
>> Cheers,
>> Donal
>>
>>
>>> On 14 Mar 2016, at 15:56, Matthew Webster <[log in to unmask]> wrote:
>>>
>>> Hi Donal,
>>> Correct - the file is the max stat value for each permutation. Note that if you happen to have saved the standard output from randomise, the critical (95%) output will be output at the end of each contrast reading something like:
>>> Critical Value for: output_vox_corrp_fstat1 is: 519.41.
>>>
>>> Kind Regards
>>> Matthew
>>>
>>>> Hi Matthew,
>>>>
>>>> Thanks for the info. Can I ask (ahead of rerunning randomise) what the format of the -N text file output is? Do I get the maximum cluster size value from each of my permutations?
>>>>
>>>> I guess I can then order them in size from smallest to largest, and move to the value appearing 95% of the way through in order to determine the threshold cluster size.
>>>>
>>>> Cheers,
>>>> Donal
>>>>
>>>>
>>>>> On 10 Mar 2016, at 23:16, Matthew Webster <[log in to unmask]> wrote:
>>>>>
>>>>> Hello Donal,
>>>>> Cluster isn't the right tool to use here - you need to enable the '-N' option in randomise to obtain the null-distribution of cluster values for each stat - you can then find the minimum significant cluster size at any percentile.
>>>>>
>>>>> Hope this helps,
>>>>> Kind Regards
>>>>> Matthew
>>>>>
>>>>>> Dear experts,
>>>>>>
>>>>>> I am interested in knowing what the minimum significant cluster size is in my output from randomise when I use the “-c” option. I have tried using the "--minclustersize” argument, but nothing additional is provided in the output.
>>>>>>
>>>>>> I would like to compare the size of the cluster I actually observe to the minimum cluster size observable by chance given a FWE corrected p-value of < 0.05.
>>>>>>
>>>>>> Many thanks for your help,
>>>>>> Donal
>>>>>>
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