Dear allstat
How to calculate area under ROC curve?
I have 37 subjects (25 positive and 12 negative) based on the golden
standard test and the values of criterion variable under investigation range
from 261 mIU/mL to 980000 mIU/mL.
Regarding the calculation of area under curve (AUC) in ROC by using NCSS
software .. the software asks for intervals at which it calculate the
sensitivity, specificity, NPV, PPV.
I tried different intervals, upon each trial the AUC differs .. so, I need
help to adjust the number of intervals so I get the correct AUC value.
Many Thanks
Dr. Wael Mahmoud
Ain Shams University Hospitals
Cairo
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