Question

Problem #3: In a patient study for multiple sclerosis (MS), 32 of the 100 patients studied actually have MS. For the data given below.complete the two by two decision matrix and construct an ROC curve and plot it. The number of lesions (50,40,30,20 or 10) correspond to the threshold value for designating MS as the diagnosis. (hint: TP+FN-32;FP+TN-100-32.) (10 points) T-40 lesions T-20 lesions T-10 lesions T-50 lesions 20 T-30 lesions 16 3 Positive (TP. Positive IFP Negative Negative (end)

Answer 1

TE 40 Jsians T-50 lasiong Discove 1 TRit Tve 2 21 67 Teat 30 - ve

T 20 Jesiong T 30 Jasjou 3 16 22 65 16 62 JO TE1O iong 28 12 56

3 XI006251 32 Sersitivty (S) Specilidy ( 8X100= 25 7 32 IT40 SM 1 67 x10098.53 /. 68 Sp 11
T=30

Sn=:16/32*100 = 50%

Sp= 65/68 * 100= 95.59%

Sn 22 yI00 6875 T-90 32 SP= 62 X1009 1.18 / 68 T- 10 87.5 1 28X100 Sn 32 SP 56 x /0082.35% 68 1l

90f T-10 clediit T 20 ot 607 T-30 SM 304 T-40 20- 20 1e0-Sp 60 t