EMC E20-007 Online Practice Questions and Exam Preparation

EMC E20-007 Online Questions & Answers

• Question 31:

  In which phase of the data analytics lifecycle do Data Scientists spend the most time in a project?

  A. Discovery
  B. Data Preparation
  C. Model Building
  D. Communicate Results
  B. Data Preparation

• Question 32:

  You submit a MapReduce job to a Hadoop cluster. However, you notice that although the job was successfully submitted, it is not completing. What should be done to identify the issue?

  A. Ensure TaskTracker is running
  B. Ensure JobTracker is running
  C. Ensure NameNode is running
  D. Ensure DataNode is running
  A. Ensure TaskTracker is running

• Question 33:

  A data scientist is asked to implement an article recommendation feature for an on-line magazine. The magazine does not want to use client tracking technologies such as cookies or reading history. Therefore, only the style and subject matter of the current article is available for making recommendations. All of the magazine's articles are stored in a database in a format suitable for analytics.

  Which method should the data scientist try first?

  A. K Means Clustering
  B. Naive Bayesian
  C. Logistic Regression
  D. Association Rules
  A. K Means Clustering

• Question 34:

  If R factors are categorical variables, which data classification level are they most closely related?

  A. Nominal
  B. Ordinal
  C. Interval
  D. Ratio
  A. Nominal

• Question 35:

  You are having a discussion with a business colleague. The colleague mentions that they want to perform K-means clustering on text file data stored in HDFS. Which tool should be recommended?

  A. Mahout
  B. HBase
  C. Scribe
  D. Sqoop
  A. Mahout

• Question 36:

  A Data Scientist is assigned to build a model from a reporting data warehouse. The warehouse contains data collected from many sources and transformed through a complex, multi-stage ETL process. What is a concern the data scientist should have about the data?

  A. It is too processed
  B. It is not structured
  C. It is not normalized
  D. It is too centralized
  A. It is too processed

• Question 37:

  The average purchase size from your online sales site is $17, 200. The customer experience team believes a certain adjustment of the website will increase sales. A pilot study on a few hundred customers showed an increase in average purchase size of $1.47, with a significance level of p=0.1.

  The team runs a larger study, of a few thousand customers. The second study shows an increased average purchase size of $0.74, with a significance level of 0.03. What is your assessment of this study?

  A. The change in purchase size is not practically important, and the good p-value of the second study is probably a result of the large study size.
  B. The change in purchase size is small, but may aggregate up to a large increase in profits over the entire customer base.
  C. The difference in the change in purchase size between the two studies is troubling; The team should run another, larger study.
  D. The p-value of the second study shows a statistically significant change in purchase size. The new website is an improvement.
  A. The change in purchase size is not practically important, and the good p-value of the second study is probably a result of the large study size.

• Question 38:

  Assume that you have a data frame in R. Which function would you use to display descriptive statistics about this variable?

  A. summary
  B. str
  C. attributes
  D. levels
  A. summary

• Question 39:

  Refer to the Exhibit.

  

  In the Exhibit, the table shows the values for the input Boolean attributes "A", "B", and "C". It also shows the values for the output attribute "class". Which decision tree is valid for the data?

  A. Tree B
  B. Tree A
  C. Tree C
  D. Tree D
  A. Tree B

• Question 40:

  You have scored your Na飗e 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 = 262/277 Recall = 262/288
  B. Precision =262/288 Recall = 262/277
  C. Precision = 277/262 Recall = 288/262
  D. Precision = 288/262 Recall = 277/262
  A. Precision = 262/277 Recall = 262/288