Question

Question 4 _(10 Marks) Assuming a total sample of 1079 persons, among which 520 persons are having autism and 559 are healthy persons. When we pass the data of 520 autism patients into the KNN classifier, it correctly predicted "220" patients as autism category and the remaining patients into healthy category. Similarly, from 559 healthy persons, the KNN categorize "100" as autism patients and the remaining as healthy persons. In the above scenario, if "autism" il considered as “positive class" and "healthy person" is considered as negative class then find the: a. True Positive b. True Negative C. False Positive d. False Negative e. Sensitivity (True positive rate) f. Specificity (True negative rate) 8. Accuracy h. Precision i. Draw the confusion matrix

Answer 1

I did part (i) first because it is easier to do calculations and predict positives and negatives if the confusion matrix is ready :)

Page No. Date : 1 Awe Total samples = 1079 autisin 1520 559 i Actual Predicted autisme healthy (tve) autian 220 T7 (- ve healthy EP 300 EN 520 459 TN 559 759 1079 320 = 459 PIT a) True Positive (TI)= 220 6) True negative (TW) c.) false positive (FP) d) false negative (FN) = 300 e) Sensitivity 100 A - 0.324 Т? TP+ EN 220 220 +459 22 18) specificity & TN 459 457+100 0.821 INTFI la 9) A curacy = TN + TP TN + TP + FN IFP = 2.10 + 459 220 +459 +100300 = 0.629 f) Precision = T1 220 0.687 TPAPP 220 + 100

By mistake in (e) part in the denominator instead of FN i took TN while calculating, please while solving change 459 to 300. Rest is fine.