Question

Answer the following questions 3. (a) Consider the contingency table below and compute the ACCURACY rate and ERROR rate for model M1. MODEL M1 PREDICTED CLASS Class-Yes Class No ACTUAL Class Yes 10 70 CLASS Class No 10 10 (b) Consider the contingency table below and compute the ACCURACY rate and ERROR rate for model M2 MODEL M2 PREDICTED CLASS Class Yes Class-No ACTUAL Class-Yes 70 CLASS Class No 10 20 (c) Given the following cost matrix, compute the cost of the above classification model Cost Matrix PREDICTED CLASS ACTUAL Cai Yes No CLASS -1 100 + 1 0

Answer 1

3).

a) From the given model M1,we have

Total = n = (70+10+10+10) = 100, True negative (TN) = 70 , True positive (TP) = 10 , False negative (FN) = 10 , False positive (FP) = 10

So, Accuracy = (TP+TN)/n = (10+70)/100 = 0.8,

Error Rate = (FP+FN)/n = (10+10)/100 = 0.2

b) From the given model M2, we have

Total = n = 70+0+20+10 = 100 , TN = 70 ,TP = 10, FN = 20 , FP = 0. So,

Accuracy = (TP + TN)/n = (10+70)/100 = 0.8,

Error Rate = (FP + FN)/n = (0+20)/100 = 0.2.

c) Cost for model M1 = 70(-1) + 10(100) + 10(1) +10(0)

= ( -70+1000+10+0) = 940

Cost for model M2 = 70(-1) + 0(100) + 20(1) + 10(0)

= (-70+0+20+0) = (-50).