[ncl-talk] Fw: Two-tailed student

[Morteza Qadimi]

 Hi,

I need to separate CP and EP El Nino years from 1979-2016 by the method used in "A new method to classify ENSO events into eastern and central Pacific types". I've calculated EOF and pattern correlation coefficient as mentioned in the paper. I've obtained a 1D array (Say EPC1 Index) which is the 1st pattern correlation coefficient. The author says about the EPC:
" The EP type El Niño is defined as the case when the EPC1 index is equal to or greater than 0.79 which is significant at the 90% confidence level from the two-tailed Student’s t-test."
How can i calculate 0.79 for my own data? I saw the "student_t(t, df)" function of NCL. Should i use this function? if yes, what are t and df variables? is t = EPC1? so what is df array?
Sincerely,Morteza  
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