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CompTIA DA0-001 Practice Test - Questions Answers, Page 15

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Randy scored 76 on a math test, Katie scored 86 on a science test, Ralph scored 80 on a history test, and Jean scored 80 on an English test. The table below contains the mean and standard deviation of the scores for each of the courses:

Using this information, which of the following students had the BEST score?

A.
Randy
A.
Randy
Answers
B.
Katie
B.
Katie
Answers
C.
Ralph
C.
Ralph
Answers
D.
Jean
D.
Jean
Answers
Suggested answer: B

Explanation:

To compare the students' scores, we need to standardize them by using the z-score formula, which is:

z = (x - µ) / σ

where x is the raw score, µ is the mean, and s is the standard deviation. The z-score tells us how many standard deviations a score is above or below the mean. A higher z-score means a better score relative to the average.

Using the table, we can calculate the z-scores for each student as follows:

Randy: z = (76 - 70) / 2 = 3 Katie: z = (86 - 80) / 3 = 2 Ralph: z = (80 - 75) / 2 = 2.5 Jean: z = (80 - 90) / 1 = -10

The student with the highest z-score is Randy, with a z-score of 3. This means that Randy scored 3 standard deviations above the mean in math, which is the best performance among the four students. Therefore, the correct answer is A.

Reference: Comparing with z-scores (video) | Z-scores | Khan Academy, 17 Important Data Visualization Techniques | HBS Online

A financial institution is reporting on sales performance to a company at the account level. Due to the sensitive nature of the government the does il with, some account information is not shown.

Which of the following fields should be masked?

A.
Sales volume
A.
Sales volume
Answers
B.
Start date
B.
Start date
Answers
C.
Product name
C.
Product name
Answers
D.
Customer name
D.
Customer name
Answers
Suggested answer: D

Explanation:

Customer name is the field that should be masked, because it contains sensitive information that could identify the government accounts that the financial institution deals with. Masking is a technique that replaces or obscures sensitive data with dummy or random data, such as asterisks or hashes. Masking can help protect the privacy and security of the data, while still allowing for some analysis and reporting. Therefore, the correct answer is D. Reference: [Data Masking | Definition, Techniques & Examples - Talend], [Data masking - Wikipedia]

'Which of the following is the BEST reason to use database views instead of tables?

A.
Views reduce the need for repetitive, complex data joins.
A.
Views reduce the need for repetitive, complex data joins.
Answers
B.
Views allow for the storage of temporary data. whereas tables do not.
B.
Views allow for the storage of temporary data. whereas tables do not.
Answers
C.
Views allow for the joining of multiple data sources, whereas tables do not.
C.
Views allow for the joining of multiple data sources, whereas tables do not.
Answers
D.
Views can be used to restrict sensitive information.
D.
Views can be used to restrict sensitive information.
Answers
Suggested answer: A

Explanation:

Views are virtual tables that are created by querying one or more base tables or other views. Views do not store any data, but only show the result of a query. One of the main advantages of using views is that they can reduce the need for repetitive, complex data joins. For example, if a query involves joining multiple tables with many conditions, creating a view can simplify the query and make it easier to reuse. Therefore, the correct answer is A. Reference: [What is a Database View? | Definition & Examples - Vertabelo], [Database Views - GeeksforGeeks]

A data analyst needs to create a data visualization that aids in un the cumulative impact of sequentially introduced values that are positive or negative. Which of the following data visualization methods should the analyst use?

A.
A bubble chart
A.
A bubble chart
Answers
B.
A waterfall chart
B.
A waterfall chart
Answers
C.
A scatter plot
C.
A scatter plot
Answers
D.
A line chart
D.
A line chart
Answers
Suggested answer: B

Explanation:

A waterfall chart is a type of data visualization that shows the cumulative impact of sequentially introduced values that are positive or negative. A waterfall chart typically has an initial value and a final value, with intermediate values shown as floating columns that either add to or subtract from the initial value. A waterfall chart can help visualize how different factors contribute to a net change in a value over time. Therefore, the correct answer is B. Reference: [Waterfall Chart | Definition & Examples - Investopedia], [Waterfall Charts in Excel | How to Create Waterfall Chart in Excel?] 4of30

Given the data below:

In which of the following file formats is the data presented?

A.
Xs
A.
Xs
Answers
B.
CSV
B.
CSV
Answers
C.
RIF
C.
RIF
Answers
D.
XML
D.
XML
Answers
Suggested answer: B

Explanation:

The data is presented in a CSV (comma-separated values) file format, which is a plain text format that stores tabular data. Each line of the file is a data record, and each record consists of one or more fields separated by commas. The first line of the file usually contains the names of the fields, also known as the header. In this case, the data has four fields: Name, Age, Gender, and Occupation.

Therefore, the correct answer is B. Reference: CSV File (What It Is & How to Open One), Commaseparated values - Wikipedia

The current date is July 14, 2020. A data analyst has been asked to create a report that shows the company's year-over-year Q2 2020 sales. Which of the following reports should the analyst compare?

A.
A Q2 2020 and Q4 2019
A.
A Q2 2020 and Q4 2019
Answers
B.
YTD 2020 and YTD 2019
B.
YTD 2020 and YTD 2019
Answers
C.
Q2 2020 and Q2 2019
C.
Q2 2020 and Q2 2019
Answers
D.
Q2 2020 and Q2 2021
D.
Q2 2020 and Q2 2021
Answers
Suggested answer: C

Explanation:

To create a report that shows the company's year-over-year Q2 2020 sales, the analyst should compare the sales data from Q2 2020 and Q2 2019. Year-over-year (YoY) analysis is a method of comparing the performance of a business or a financial instrument over the same period in different years. It helps to identify trends, growth patterns, and seasonal fluctuations. Q2 refers to the second quarter of a year, which is usually from April to June. Therefore, the correct answer is C.

Reference: YoY - Year over Year Analysis - Definition, Explanation & Examples, What is an Annual Sales Report: Definition, metrics, and tips - Snov.io

Which of the following differentiates a flat text file from other data types?

A.
Data is separated by a delimiter.
A.
Data is separated by a delimiter.
Answers
B.
Data is stored in defined rows.
B.
Data is stored in defined rows.
Answers
C.
Data is defined with key-value pairs.
C.
Data is defined with key-value pairs.
Answers
D.
Data is housed in a markup language.
D.
Data is housed in a markup language.
Answers
Suggested answer: A

Explanation:

A flat text file is a type of data file that contains only plain text without any formatting or markup.

Data in a flat text file is usually separated by a delimiter, which is a character that marks the boundary between different fields or values. For example, a comma-separated values (CSV) file is a flat text file that uses commas as delimiters. Other common delimiters are tabs, spaces, semicolons, and pipes. Therefore, the correct answer is A. Reference: Plain text - Wikipedia, Comparison of document markup languages - Wikipedia

Which of the following is an example of a data-mining ETL tool?

A.
SSIS
A.
SSIS
Answers
B.
Stata
B.
Stata
Answers
C.
SPSS
C.
SPSS
Answers
D.
Cognos
D.
Cognos
Answers
Suggested answer: A

Explanation:

A data-mining ETL tool is a software application that performs extract, transform, and load (ETL) operations on data for data mining purposes. Data mining is the process of discovering patterns, trends, and insights from large and complex data sets. ETL tools help to prepare the data for analysis by extracting data from various sources, transforming data into a consistent and suitable format, and loading data into a data warehouse or other destination. SSIS (SQL Server Integration Services) is an example of a data-mining ETL tool that is part of Microsoft SQL Server. SSIS provides graphical tools and wizards for building and debugging ETL packages that can work with various data sources and destinations. Therefore, the correct answer is A. Reference: [Data Mining - SQL Server Integration Services (SSIS) | Microsoft Docs], [What Is Data Mining? | Oracle]

Which of the ing is the correct ion for a tab-delimited spre file?

A.
tap
A.
tap
Answers
B.
tar
B.
tar
Answers
C.
sv
C.
sv
Answers
D.
az
D.
az
Answers
Suggested answer: C

Explanation:

A tab-delimited spreadsheet file is a type of flat text file that uses tabs as delimiters to separate data values in a table. The file extension for a tab-delimited spreadsheet file is usually .tsv, which stands for tab-separated values. Therefore, the correct answer is C. Reference: [Tab-separated values -Wikipedia], [What is a TSV File? | How to Open, Edit & Convert TSV Files]

A data analyst is developing a dashboard to track and monitor metrics. Which of the following best practices should be taken into during the FIRST pment process?

A.
Create a A Aupirarrame:
A.
Create a A Aupirarrame:
Answers
B.
Deploy to production.
B.
Deploy to production.
Answers
C.
Copy a dashboard design from the Internet.
C.
Copy a dashboard design from the Internet.
Answers
D.
Develop a dashboard.
D.
Develop a dashboard.
Answers
Suggested answer: A

Explanation:

A dashboard is a graphical display that summarizes and presents key performance indicators (KPIs) and metrics for a business or a project. A dashboard should be clear, concise, and easy to understand.

To develop a dashboard, one of the best practices is to create a wireframe or a mockup first. A wireframe or a mockup is a low-fidelity sketch or prototype of the dashboard layout and design, which helps to define the scope, requirements, and functionality of the dashboard. Creating a wireframe or a mockup can help to save time and resources, as well as to get feedback from stakeholders and users before deploying the dashboard to production. Therefore, the correct answer is A. Reference: [Dashboard Design Best Practices: 4 Key Principles | Toptal], [How to Create an Effective Dashboard (with Examples) | Tableau]

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