Table 3

Hypothetical data for two ordered markers, A and B

Subjects without cancer (N = 1000)

Subjects with cancer (N = 100)



A = 1

A = 2

A = 3

B only

A = 1

A = 2

A = 3

B only


B = 1

640

80

80

800

20

0

0

20

B = 2

80

10a

10a

100e

0

20b

0b

20f

B = 3

80

10a

10a

100e

0

0b

60b

60f

A only

800

100c

100c

20

20d

60d


For A and B combined; aFalse positive rate (FPR) of indicated region (10+10+10+10)/1000=. 04; bTrue positive rate (TPR) of indicated region = (20 +0+0+60)/100=. 80 For A only; cFalse positive rate (FPR) of indicated region =(100+100)/1000=. 20; dTrue positive rate (TPR) of indicated region = (20+60)/100=. 80 For B only; eFalse positive rate (FPR) of indicated region =(100+100)/1000= .20; fTrue positive rate (TPR) of indicated region = (20+60)/100=.80

Baker et al. BMC Medical Research Methodology 2002 2:4   doi:10.1186/1471-2288-2-4

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