Re: confidence interval/level

Comments on the Determination of Significance Levels
of the Coherence Statistic
Paul Julian
Journal of the Atmospheric Sciences, 1975
Volume 12, pp836-837

http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281975%29032%3C0836%3ACOTDOS%3E2.0.CO%3B2

eg:
       coh = .5
       df = 6
       p = 1.-(1.-coh)**(df/2.-1.)
       print("p="+p)

On 9/18/13 8:54 AM, 朱学明 wrote:
> Hi Dennis,
> can you show me how does NCL caculate the spec@coher_probability?
> Thanks.
>
> 2013-09-18
>
>
>
> 朱学明
>
>
>
> 发件人：Dennis Shea <shea@ucar.edu>
> 发送时间：2013-09-18 07:29
> 主题：Re: [ncl-talk] confidence interval/level
> 收件人："朱学明"<557xiaozhu@163.com>
> 抄送："ncl-talk@ucar.edu USERS"<ncl-talk@ucar.edu>
>
> spec = specxy_anal(x,y,d,sm,pct)
> PHASE = spec@phase
> PHASE@_FillValue = 1e20
> PHASE = where(spec@coher_probability(1).le.0.95,PHASE@_FillValue,PHASE)
>
> =========
> See: http://www.ncl.ucar.edu/Applications/xy.shtml#ex25
>
> The right (R) plot should
>
>
> resR = True ; plot mods desired
> resR@xyMarkLineModes = "Markers" ; choose which have markers
> resR@xyMarkers = 16 ; choose type of marker
> resR@xyMarkerColor = "red" ; Marker color
> resR@xyMarkerSizeF = 0.005 ; Marker size (default 0.01)
>
>
> plot = gsn_csm_xy2(wks,spec@frq,spec@coher,PHASE,resL,resR)
>
>
> On 9/17/13 4:04 PM, 朱学明 wrote:
>> Hi all,
>> I have tried to use the function specxy_anal get the coherance and phase of two timeseries data based on the example script spec_2.ncl. But I just want to get the coherence and phase satisfy the 0.95 confidence level, the picture likes that in the attachment. How can I do that?
>> It looks like that the output of function specx_ci is not what I want.
>>
>> Any help would be appreciated. Thanks.
>>
>> 2013-09-18
>>
>>
>>
>> 朱学明
>>
>>
>>
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Received on Wed Sep 18 11:13:24 2013