EMC EMC Specialist E20-026 Questions & Answers

• Question 31:

  What is a property of window functions in SQL commands?

  A. They can be used to calculate moving averages over various intervals.

  B. They group rows into a single output row.

  C. They can be used between the keywords FROM and WHERE in a SELECT command.

  D. They don't require ordering of data within a window.

  Correct Answer: A

• Question 32:

  You are attempting to find the Euclidean distance between two centroids:

  Centroid A's coordinates: (X = 2, Y = 4)

  Centroid B's coordinates (X = 8, Y = 10)

  Which formula finds the correct Euclidean distance?

  A. SQRT((2-8)2+(4-10)2) or 8.49

  B. SQRT(((2-8) x 2) + ((4-10) x 2)) or 12.17

  C. ((2-8)2+(4-10)2) or 72

  D. ((2-8) x 2 + (4-10) x 2) or 148

  Correct Answer: A

• Question 33:

  In data visualization, which type of chart is recommended to represent frequency data?

  A. Line chart

  B. Histogram

  C. Q-Q chart

  D. Scatterplot

  Correct Answer: B

• Question 34:

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

  A. Run a pilot

  B. Try different analytical techniques

  C. Try different variables

  D. Transform existing variables

  Correct Answer: A

• Question 35:

  Refer to the exhibit.

  You are asked to write a report on how specific variables impact your client's sales using a data set

  provided to you by the client. The data includes 15 variables that the client views as directly related to

  sales, and you are restricted to these variables only.

  After a preliminary analysis of the data, the following findings were made:

  1.

  Multicollinearity is not an issue among the variables

  2.

  Only three variables--A, B, and C--have significant correlation with sales You build a linear regression

  model on the dependent variable of sales with the independent variables of A, B, and C. The results of the

  regression are seen in the exhibit.

  Which interpretation is supported by the analysis?

  

  A. Variables A,B,and C are significantly impacting sales,but are not effectively estimating sales

  B. Variables A,B,and C are significantly impacting sales and are effectively estimating sales

  C. Due to the R2 of 0.10,the model is not valid ?the linear regression should be re-run with all 15 variables forced into the model to increase the R2

  D. Due to the R2 of 0.10,the model is not valid ?a different analytical model should be attempted

  Correct Answer: A

• Question 36:

  Which word or phrase completes the statement? A data warehouse is to a centralized database for reporting as an analytic sandbox is to a _______?

  A. Collection of data assets for modeling

  B. Collection of low-volume databases

  C. Centralized database of KPIs

  D. Collection of data assets for ETL

  Correct Answer: A

• Question 37:

  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.

  Correct Answer: A

• Question 38:

  In linear regression, what indicates that an estimated coefficient is significantly different than zero?

  A. A small p-value

  B. R-squared near 1

  C. R-squared near 0

  D. The estimated coefficient is greater than 3

  Correct Answer: A

• Question 39:

  Which graphical representation shows the distribution and multiple summary statistics of a continuous variable for each value of a corresponding discrete variable?

  A. box and whisker plot

  B. dotplot

  C. scatterplot

  D. binplot

  Correct Answer: A

• Question 40:

  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

  Correct Answer: A