Data Science

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Question 1
Marks : +2 | -2
Pass Ratio : 100%
Point out the correct statement.
The difference between the class centroids and the overall centroid is used to measure the variable influence
The Bagged Trees output contains variable usage statistics
Boosted Trees uses different approach as a single tree
None of the mentioned
Explanation:
The larger the difference between the class centroid and the overall center of the data, the larger the separation between the classes.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The function preProcess estimates the required parameters for each operation.
True
False
Explanation:
predict.preProcess is used to apply them to specific data sets.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Which of the following can be used to generate balanced cross–validation groupings from a set of data?
createFolds
createSample
createResample
none of the mentioned
Explanation:
createResample can be used to make simple bootstrap samples.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Which of the following function can be used to identify near zero-variance variables?
zeroVar
nearVar
nearZeroVar
all of the mentioned
Explanation:
The saveMetrics argument can be used to show the details and usually defaults to FALSE.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which of the following can be used to impute data sets based only on information in the training set?
postProcess
preProcess
process
all of the mentioned
Explanation:
This can be done with K-nearest neighbors.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Which of the following can be used to create sub–samples using a maximum dissimilarity approach?
minDissim
maxDissim
inmaxDissim
all of the mentioned
Explanation:
Splitting is based on the predictors.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Which of the following model sums the importance over each boosting iteration?
Boosted trees
Bagged trees
Partial least squares
None of the mentioned
Explanation:
gbm package can be used here.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
The preProcess class can be used for many operations on predictors.
True
False
Explanation:
Operations include centering and scaling.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following function can create the indices for time series type of splitting?
newTimeSlices
createTimeSlices
binTimeSlices
none of the mentioned
Explanation:
Rolling forecasting origin techniques are associated with time series type of splitting.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
For most classification models, each predictor will have a separate variable importance for each class.
True
False
Explanation:
The exceptions are classification trees, bagged trees and boosted trees.