EMC E20-026 Online Practice Questions and Exam Preparation

EMC E20-026 Online Questions & Answers

• Question 11:

  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 12:

  Refer to the exhibit.

  You have plotted the distribution of savings account sizes for your bank. How would you proceed, based on this distribution?

  

  A. The data is extremely skewed. Replot the data on a logarithmic scale to get a better sense of it.
  B. The data is extremely skewed,but looks bimodal; replot the data in the range 2,500-10,000 to be sure.
  C. The accounts of size greater than 2500 are rare,and probably outliers. Eliminate them from your future analysis.
  D. The data is extremely skewed. Split your analysis into two cohorts: accounts less than 2500,and accounts greater than 2500
  A. The data is extremely skewed. Replot the data on a logarithmic scale to get a better sense of it.

• Question 13:

  Refer to the Exhibit.

  You are working on creating an OLAP query that outputs several rows of with summary rows of subtotals and grand totals in addition to regular rows that may contain NULL as shown in the exhibit. Which function can you use in your query to

  distinguish the row from a regular row to a subtotal row?

  

  A. GROUPING
  B. RANK
  C. GROUP_ID
  D. ROLLUP
  A. GROUPING

• Question 14:

  Which word or phrase completes the statement? A Data Scientist would consider that a RDBMS is to a Table as R is to a ______________ .

  A. Data frame
  B. List
  C. Matrix
  D. Array
  A. Data frame

• Question 15:

  You are testing two new weight-gain formulas for puppies. The test gives the results:

  Control group: 1% weight gain Formula A. 3% weight gain Formula B. 4% weight gain A one-way ANOVA returns a p-value = 0.027

  What can you conclude?

  A. Either Formula A or Formula B is effective at promoting weight gain.
  B. Formula B is more effective at promoting weight gain than Formula A.
  C. Formula A and Formula B are both effective at promoting weight gain.
  D. Formula A and Formula B are about equally effective at promoting weight gain.
  A. Either Formula A or Formula B is effective at promoting weight gain.

• Question 16:

  A data scientist is given an R data frame, "empdata", with the columns Age, Salary, Occupation, Education, and Gender. The data scientist would like to examine only the Salary and Occupation columns for ages greater than 40. Which command extracts the appropriate rows and columns from the data frame?

  A. empdata[empdata$Age > 40,c("Salary","Occupation")]
  B. empdata[c("Salary","Occupation"),empdata$Age > 40]
  C. empdata[Age > 40,("Salary","Occupation")]
  D. empdata[,c("Salary","Occupation")]$Age > 40
  A. empdata[empdata$Age > 40,c("Salary","Occupation")]

• Question 17:

  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 JobTracker is running
  C. Ensure that the NameNode is running
  D. Ensure that a DataNode is running
  A. Ensure that the TaskTracker is running.

• Question 18:

  What describes a true property of Logistic Regression method?

  A. It is robust with redundant variables and correlated variables.
  B. It handles missing values well.
  C. It works well with discrete variables that have many distinct values.
  D. It works well with variables that affect the outcome in a discontinuous way.
  A. It is robust with redundant variables and correlated variables.

• Question 19:

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

  A. Pie chart
  B. Area chart
  C. Stacked bar chart
  D. ROC curve
  D. ROC curve

• Question 20:

  You do a Student's t-test to compare the average test scores of sample groups from populations A and B. Group A averaged 10 points higher than group B. You find that this difference is significant, with a p-value of 0.03. What does that mean?

  A. There is a 3% chance that you have identified a difference between the populations when in reality there is none.
  B. The difference in scores between a sample from population A and a sample from population B will tend to be within 3% of 10 points.
  C. There is a 3% chance that a sample group from population A will score 10 points higher that a sample group from population B.
  D. There is a 97% chance that a sample group from population A will score 10 points higher that a sample group from population B.
  A. There is a 3% chance that you have identified a difference between the populations when in reality there is none.