### These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

Course Name: INTRODUCTION TO MACHINE LEARNING

Q1. You have 2 binary classifiers A and B. A has accuracy=0% and B has accuracy=50%. Which classifier is more useful?
a. A
b. B
c. Both are good
d. Cannot say

Q2. You have 2 multi-class classifiers A and B. A has accuracy=0% and B has accuracy=50%. Which classifier is more useful?
a. A
b. B
c. Both are good
d. Cannot say

These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

Q3. Using the bootstrap approach for sampling, the new dataset will have _________ of the original samples on expectation.
a. 50.0%
b. 56.8%
c. 63.2%
d. 73.6%

Q4. You have a special case where your data has 10 classes and is sorted according to target labels. You attempt 5-fold cross validation by selecting the folds sequentially. What can you say about your resulting model?
a. It will have 100% accuracy.
b. It will have 0% accuracy.
c. Accuracy will depend on how good the model does.
d. Accuracy will depend on the compute power available for training.

Answer: d. Accuracy will depend on the compute power available for training.

These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

Q5. Given the following information
What is the precision and recall?
a. 0.5, 0.4375
b. 0.7, 0.636
c. 0.6, 0.636
d. 0.7, 0.4375
e. None of the above

Answer: e. None of the above

Q6. AUC for your newly trained model is 0.5. Is your model prediction completely random?
a. Yes
b. No
c. ROC curve is needed to derive this conclusion
d. Cannot be determined even with ROC

Answer: d. Cannot be determined even with ROC

These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

Q7. What is the effect of using bagging on weak classifiers for variance?
a. Increases variance
b. Reduces variance
c. Does not change

Q8. You are building a model to detect cancer. Which metric will you prefer for evaluating your model?
a. Accuracy
b. Sensitivity
c. Specificity
d. MSE

These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

Q9. You are building a model to detect a mild medical condition for which further testing costs are extremely expensive. Which metric will you prefer for evaluating your model?
a. Accuracy
b. Sensitivity
c. Specificity
d. MSE

Q10. A: Boosting takes many weak learners and combines them into a strong learner.
B: Boosting determines the proportion of importance each weak learner should be assigned and weighs its prediction by it and combines them to make the final prediction.

a. A is True. B is True. B is the correct explanation for A.
b. A is True. B is True. B is not the correct explanation for A.
c. A is True. B is False.
d. Both A and B are False.

Answer: c. A is True. B is False.

These are the solutions of NPTEL INTRODUCTION TO MACHINE LEARNING ASSIGNMENT 7 WEEK 7

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