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Total questions: 25
Worksheet time: 1hrs 5mins
Which of the following is a widely used and effective machine learning algorithm based on the idea of bagging?
Decision Tree
Regression
Classification
Random Forest
To find the minimum or the maximum of a function, we set the gradient to zero because:
The value of the gradient at extrema of a function is always zero
Depends on the type of problem
Both A and B
None of the above
The most widely used metrics and tools to assess a classification model are:
Confusion matrix
Cost-sensitive accuracy
Area under the ROC curve
All of the above
Which of the following is a good test dataset characteristic?
Large enough to yield meaningful results
Is representative of the dataset as a whole
Both A and B
None of the above
Which of the following is a disadvantage of decision trees?
Factor analysis
Decision trees are robust to outliers
Decision trees are prone to be overfit
None of the above
How do you handle missing or corrupted data in a dataset?
Drop missing rows or columns
Replace missing values with mean/median/mode
Assign a unique category to missing values
All of the above
What is the purpose of performing cross-validation?
To assess the predictive performance of the models
To judge how the trained model performs outside the sample on test data
Both A and B
Why is second order differencing in time series needed?
To remove stationarity
find the maxima or minima at the local point
Both A and B
None of the above
When performing regression or classification, which of the following is the correct way to preprocess the data?
Normalize the data → PCA → training
PCA → normalize PCA output → training
Normalize the data → PCA → normalize PCA output → training
None of the above
Which of the folllowing is an example of feature extraction?
Constructing bag of words vector from an email
Applying PCA projects to a large high-dimensional data
Removing stopwords in a sentence
All of the above
What is pca.components_ in Sklearn?
Set of all eigen vectors for the projection space
Matrix of principal components
Result of the multiplication matrix
None of the above options
Which of the following is true about Naive Bayes ?
Assumes that all the features in a dataset are equally important
Assumes that all the features in a dataset are independent
Both A and B
None of the above options
Which of the following statements about regularization is not correct?
Using too large a value of lambda can cause your hypothesis to underfit the data.
Using too large a value of lambda can cause your hypothesis to overfit the data.
Using a very large value of lambda cannot hurt the performance of your hypothesis.
None of the above
How can you prevent a clustering algorithm from getting stuck in bad local optima?
Set the same seed value for each run
Use multiple random initializations
Both A and B
None of the above
Which of the following techniques can be used for normalization in text mining?
Stemming
Lemmatization
Stop Word Removal
Both A and B
In which of the following cases will K-means clustering fail to give good results? 1) Data points with outliers 2) Data points with different densities 3) Data points with nonconvex shapes
1 and 2
2 and 3
1, 2, and 3
1 and 3
Which of the following is a reasonable way to select the number of principal components "k"?
Choose k to be the smallest value so that at least 99% of the varinace is retained.
Choose k to be 99% of m (k = 0.99*m, rounded to the nearest integer).
Choose k to be the largest value so that 99% of the variance is retained.
Use the elbow method
You run gradient descent for 15 iterations with a=0.3 and compute J(theta) after each iteration. You find that the value of J(Theta) decreases quickly and then levels off. Based on this, which of the following conclusions seems most plausible?
Rather than using the current value of a, use a larger value of a (say a=1.0)
Rather than using the current value of a, use a smaller value of a (say a=0.1)
a=0.3 is an effective choice of learning rate
None of the above
What is a sentence parser typically used for?
It is used to parse sentences to check if they are utf-8 compliant.
It is used to parse sentences to derive their most likely syntax tree structures.
It is used to parse sentences to assign POS tags to all tokens.
It is used to check if sentences can be parsed into meaningful tokens.
Suppose you have trained a logistic regression classifier and it outputs a new example x with a prediction ho(x) = 0.2. This means
Our estimate for P(y=1 | x)
Our estimate for P(y=0 | x)
Our estimate for P(y=1 | x)
Our estimate for P(y=0 | x)
Question 21-24: Consider the following figure for answering the next few questions. In the figure, X1 and X2 are the two features and the data point is represented by dots (-1 is negative class and +1 is a positive class). And you first split the data based on feature X1(say splitting point is x11) which is shown in the figure using vertical line. Every value less than x11 will be predicted as positive class and greater than x will be predicted as negative class.
Question 21: How many data points are misclassified in above image?
1
2
3
4
Question 21-24: Consider the following figure for answering the next few questions. In the figure, X1 and X2 are the two features and the data point is represented by dots (-1 is negative class and +1 is a positive class). And you first split the data based on feature X1(say splitting point is x11) which is shown in the figure using vertical line. Every value less than x11 will be predicted as positive class and greater than x will be predicted as negative class.
Question 22:
Greater than x11
Less than x11
Equal to x11
None of above
Question 21-24: Consider the following figure for answering the next few questions. In the figure, X1 and X2 are the two features and the data point is represented by dots (-1 is negative class and +1 is a positive class). And you first split the data based on feature X1(say splitting point is x11) which is shown in the figure using vertical line. Every value less than x11 will be predicted as positive class and greater than x will be predicted as negative class.
Question 23:If you consider only feature X2 for splitting. Can you now perfectly separate the positive class from negative class for any one split on X2?
Yes
No
Question 21-24: Consider the following figure for answering the next few questions. In the figure, X1 and X2 are the two features and the data point is represented by dots (-1 is negative class and +1 is a positive class). And you first split the data based on feature X1(say splitting point is x11) which is shown in the figure using vertical line. Every value less than x11 will be predicted as positive class and greater than x will be predicted as negative class.
Question 24:Now consider only one splitting on both (one on X1 and one on X2) feature. You can split both features at any point. Would you be able to classify all data points correctly?
True
False
Suppose you are building random forest model, which split a node on the attribute, that has highest information gain. In the below image, select the attribute which has the highest information gain?
Outlook
Humidity
Windy
Temperature
