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Optimal Data Analysis

Frequently Asked Questions

Why doesn’t ODA print exact p for my analysis?
Elaboration:
This question was submitted by Timothy D. Ritchie, MA, from the department of psychology of Northern Illinois University (DeKalb, IL):
"My issue concerns the production of the exact p value, as shown by the code on p. 102 and within the output after running ex59.cmd and ex59.dat. I essentially used similar syntax but do not get any exact p values in my output. Why doesn't an exact p value appear in my output as it does in the example?"

Response:
ODA software computes exact one-tail p provided the following are true:

  1. The number of observations is 1000 or fewer;
  2. The class variable has two category levels;
  3. Priors is set off, or the class membership is balanced;
  4. The optimal value (number of correct classifications) is at least 75% of the total number of observations;
  5. No ties exist on the attribute; and
  6. The problem is not GEN or weighted. When exact p is not available, the Monte Carlo procedure may be used to estimate p to any desired confidence level.
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RELATED LINKS
* System Requirements
* Troubleshooting Guide (PDF: 55KB)
* FAQs
* ODA Command List
(PDF: 197KB)
* Publications Featuring ODA (PDF: 28KB)



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