Machine Learning Practice Test

Question 1

We set the gradient to zero to obtain the minimum or maximum of a function because:

Accepted Answer

The value of the gradient at extrema of a function is always zero

Answer

Depends on the type of problem

Answer

A and B

Answer

None of these

Question 2

Which of the following machine learning algorithms is based on the principle of bagging and is extensively used and effective?

Accepted Answer

Random Forest

Answer

Classification

Answer

Decision Tree

Answer

Regression

Question 3

Which of the following is a good characteristic of a test dataset?

Accepted Answer

A and B

Answer

Is representative of the dataset as a whole

Answer

Large enough to yield meaningful results

Question 4

The following are the most regularly used metrics and tools for evaluating a classification model:

Accepted Answer

All of the above

Answer

Area under the ROC curve

Answer

Confusion matrix

Answer

Cost-sensitive accuracy

Question 5

What is the purpose of cross-validation?

Accepted Answer

Both A and B

Answer

To judge how the trained model performs outside the sample on test data

Answer

To assess the predictive performance of the models

Question 6

How do you deal with data in a dataset that is missing or corrupted?

Accepted Answer

All of the above

Answer

Replace missing values with mean/median/mode

Answer

Assign a unique category to missing values

Answer

Drop missing rows or columns

Question 7

A disadvantage of decision trees is which of the following?

Accepted Answer

Decision trees are prone to be overfit

Answer

Factor analysis

Answer

Decision trees are robust to outliers

Question 8

Which of the following is the correct technique to preprocess data before performing regression or classification?

Accepted Answer

Normalize the data -> PCA -> training

Answer

PCA -> normalize PCA output -> training

Answer

Normalize the data -> PCA -> normalize PCA output -> training

Question 9

Why is it necessary to use second-order differencing in a time series?

Accepted Answer

Both A and B

Answer

To find the maxima or minima at the local point

Answer

To remove stationarity

Answer

None of these

Question 10

In Sklearn, what is pca.components_?

Accepted Answer

Set of all eigen vectors for the projection space

Answer

Matrix of principal components

Answer

Result of the multiplication matrix

Answer

None of the above