Exercise 1:
Data were referred from the article by Hanley JA and McNeil BJ (Radiology, 148: 839-843, 1983), who proposed the ROC at the first time.
Two CT image reconstruction methods (Modality 1 and Modality 2) were compared for the ability in making differential diagnosis of normal and abnormal findings. Fifty-eight normal images and 54 abnormal images were prepared and assessed the images with 1 to 6 evaluation scores. Scores indicate 1 = ‘normal’, 2 = ‘probably normal’, 3 = ‘may be normal’, 4 = ‘may be abnormal’, 5 = ‘probably abnormal’, 6 = ‘abnormal’.
The following data chart was made. Perform the ROC analysis to evaluate which reconstruction method has superiority.
Exercise2:
The following summary is derived from sample 3 data. Perform one ROC analysis which includes calculation of the AUC, the test of the AUC against the value 0.5, and finding the optimal cutoff point with the Youden index.
