Dell Data Science Foundations (D-DS-FN-23) Free Practice Test

Question 1

You submit a MapReduce job to a Hadoop cluster and notice that although the job was successfully submitted, it is not completing.
What should you do?

A. Ensure that the TaskTracker is running.

B. Ensure that the NameNode is running

C. Ensure that the JobTracker is running

D. Ensure that a DataNode is running

Correct Answer: A

Question 2

Before building an ARMA model, how can you determine if the time series is weakly stationary?

A. Constant variance around a constant mean is apparent

B. Mean of the series is close to 0

C. Series is normally distributed

D. No trend component is apparent

Correct Answer: A

Question 3

What does R code nv <- v[v < 1000] do?

A. Sets nv to TRUE or FALSE depending on whether all elements of vector v are less than 1000

B. Selects values of vector v less than 1000, modifies v, and makes a copy to nv

C. Removes elements of vector v less than 1000 and assigns the elements >= 1000 to nv

D. Selects the values in vector v that are less than 1000 and assigns them to the vector nv

Correct Answer: D

Question 4

Which activity is performed in the Operationalize phase of the Data Analytics Lifecycle?

A. Define the process to maintain the model

B. Try different analytical techniques

C. Transform existing variables

D. Try different variables

Correct Answer: A

Question 5

A data scientist plans to classify the sentiment polarity of 10, 000 product reviews collected from the Internet.
What is the most appropriate model to use? Suppose labeled training data is available.

A. K-means clustering

B. Logistic regression

C. Naïve Bayesian classifier

D. Linear regression

Correct Answer: C

Question 6

Which term is used to describe separating a database into separate parts that can be processed in parallel?

A. Sharding

B. Deduplication

C. Replication

D. Reconstituting

Correct Answer: A

Question 7

In a user-defined aggregate function, what is FFUNC?

A. State transition function

B. Segment-level calculation function

C. Window function

D. Optional final calculation function

Correct Answer: D

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Question 8

What is an appropriate data visualization to use in a presentation for an analyst audience?

A. Stacked bar chart

B. Pie chart

C. Area chart

D. ROC curve

Correct Answer: D

Question 9

You have scored your Naïve Bayesian Classifier model on "hold out" test data for cross validation. You have determined the way the samples scored and have tabulated them as shown in the exhibit.

What are the Precision and Recall rates of the model?

A. Precision =262/288 Recall = 262/277

B. Precision = 262/277 Recall = 262/288

C. Precision = 277/262 Recall = 288/262

D. Precision = 288/262 Recall = 277/262

Correct Answer: B

Question 10

Which chart type is the most effective way to show trends over time?

A. Histogram

B. Line Chart

C. Bar Chart

D. Stacked Bar Chart

Correct Answer: B

Question 11

Which word or phrase completes the statement? Mahout is to Hadoop as MADlib is to _______.

A. Excel

B. PostgreSQL

C. SAS

D. R

Correct Answer: B

Question 12

In which phase of the analytic lifecycle would you expect to spend most of the project time?

A. Operationalize

B. Data preparation

C. Discovery

D. Communicate Results

Correct Answer: B

Question 13

After running a density plot you realize that the data has a long tail to the right. What can you do to make the dataset more normally distributed?

A. Apply a square transformation

B. Apply a logarithmic transformation

C. Use a scatter plot to obtain a better picture

D. Use a histogram to obtain a better picture

Correct Answer: B

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EMC Dell Data Science Foundations (D-DS-FN-23) Free Practice Test