CompTIA CompTIA Certifications DA0-001 Questions & Answers

• Question 161:

  Given the data below: In which of the following file formats is the data presented?

  

  A. Xs

  B. CSV

  C. RIF

  D. XML

  Correct 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. References: CSV File (What It Is and How to Open One), Comma-separated values - Wikipedia

• Question 162:

  A database consists of one fact table that is composed of multiple dimensions. Depending on the dimension, each one can be represented by a denormalized table or multiple normalized tables. This structure is an example of a:

  A. transactional schema.

  B. star schema.

  C. non-relational schema.

  D. snowflake schema.

  Correct Answer: B

  star schema is a type of database schema that consists of one fact table that is composed of multiple dimensions. A fact table contains quantitative measures or facts that are related to a specific event or transaction. A dimension table contains descriptive attributes or dimensions that provide context for the facts. A star schema is called so because it resembles a star, with the fact table at the center and the dimension tables radiating from it. A star schema is a type of dimensional schema, which is designed for data warehousing and analytical purposes. Other types of dimensional schemas include snowflake schema and galaxy schema. A snowflake schema is similar to a star schema, except that some or all of the dimension tables are normalized into multiple tables. A galaxy schema consists of multiple fact tables that share some common dimension tables. A transactional schema is a type of database schema that is designed for operational purposes, such as recording day- to-day transactions and activities. A transactional schema is usually normalized to reduce data redundancy and improve data integrity. A non-relational schema is a type of database schema that does not follow the relational model, which organizes data into tables with rows and columns. A non-relational schema can store data in various formats, such as documents, graphs, key-value pairs, etc.

• Question 163:

  Angela is aggregating data from CRM system with data from an employee system.

  While performing an initial quality check, she realizes that her employee ID is not associated with her identifier in the CRM system.

  What kind of issues is Angela facing?

  Choose the best answer.

  A. ETL process.

  B. Record linkage.

  C. ELT process.

  D. System integration.

  Correct Answer: B

  While this scenario describes a system integration challenge that can be solved with ETL or ELT, Angela is facing a Record linkage issue.

• Question 164:

  A Chief Executive Officer (CEO) is requesting more up-to-date sales data for improved visibility prior to month-end. An analyst must determine the frequency of a sales report that was previously distributed on an as-needed basis. Which of the following would be the most appropriate frequency for this report?

  A. Monthly

  B. Quarterly

  C. Weekly

  D. Every other month

  Correct Answer: C

  Explanation: The most appropriate frequency for the sales report is weekly, as this will provide the CEO with more up-to-date sales data for improved visibility prior to month-end. A weekly sales report can show the sales performance, trends, and issues of the sales team on a regular basis, and help the CEO to monitor and evaluate the progress and results of the sales activities. A weekly sales report can also help the CEO to identify and address any problems or opportunities that may arise during the month, and to make timely and informed decisions.

• Question 165:

  A web developer wants to ensure that malicious users can't type SQL statements when they asked for input, like their username/userid.

  Which of the following query optimization techniques would effectively prevent SQL Injection attacks?

  A. Indexing.

  B. Subset of records.

  C. Temporary table in the query set.

  D. Parametrization.

  Correct Answer: D

  The correct answer is D: Parametrization. Parameterized SQL queries allow you to place parameters in an SQL query instead of a constant value. A parameter takes a value only when the query is executed, allowing the query to be reused

  with different values and purposes. Parameterized SQL statements are available in some analysis clients, and are also available through the Historian SDK.

  For example, you could create the following conditional SQL query, which contains a parameter for the collector's name: SELECT* FROM ExamsDigest WHERE coursename=? ORDER BY tagname SQL Injection is best prevented through

  the use of parameterized queries.

• Question 166:

  Which of the following is the correct data type for text?

  A. Boolean

  B. String

  C. Integer

  D. Float

  Correct Answer: B

  Explanation: The correct data type for text is string. A string is a data type that represents a sequence of characters, such as letters, numbers, symbols, or spaces. A string can be enclosed by single quotes (' ') or double quotes (" ") in most programming languages. For example, `Hello', "World", and "123" are all strings. The other options are not data types for text, but for other kinds of values. A boolean is a data type that represents a logical value, either true or false. An integer is a data type that represents a whole number, such as 1, 0, or -5. A float is a data type that represents a number with a fractional part, such as 3.14, 0.5, or -2.7. Reference: Data Types - W3Schools

• Question 167:

  An e-commerce company recently tested a new website layout. The website was tested by a test group of customers, and an old website was presented to a control group. The table below shows the percentage of users in each group who made purchases on the websites: Which of the following conclusions is accurate at a 95% confidence interval?

  

  A. In Germany, the increase in conversion from the new layout was not significant.

  B. In France, the increase in conversion from the new layout was not significant.

  C. In general, users who visit the new website are more likely to make a purchase.

  D. The new layout has the lowest conversion rates in the United Kingdom.

  Correct Answer: C

  Explanation: The conclusion that is accurate at a 95% confidence interval is that in general, users who visit the new website are more likely to make a purchase. A 95% confidence interval means that we are 95% confident that the true

  difference between the two groups lies within a certain range of values. To calculate the 95% confidence interval, we can use the following formula:

  CI = (p1 - p2) ?1.96 * sqrt(p * (1 - p) * (1/n1 + 1/n2)) where p1 and p2 are the conversion rates for the test and control groups, respectively, p is the pooled conversion rate, n1 and n2 are the sample sizes for the test and control groups,

  respectively, and 1.96 is the z-score for a 95% confidence level. Using this formula, we can calculate the 95% confidence interval for each country as follows:

  Country | p1 | p2 | n1 | n2 | p | CI United States | 0.12 | 0.11 | 2000 | 2000 | 0.115 | (-0.006, 0.026) Germany | 0.06 | 0.04 | 1000 | 1000 | 0.05 | (-0.002, 0.042) United Kingdom | 0.09 | 0.07 | 1500 | 1500 | 0.08 | (-0.003, 0.053) France | 0.08 |

  0.08 | 1200 | 1200 | 0.08 | (-0.024, 0.024) Canada | 0.05 | 0.03 | 800 | 800 | 0.04 | (-0.005, 0.045) We can see that for all countries except France, the confidence interval does not include zero, which means that the difference between the test

  and control groups is statistically significant at a 95% confidence level. However, this does not mean that the difference is practically significant or meaningful for the business. To measure the practical significance, we can use another metric

  called lift, which is the percentage increase or decrease in conversion rate from the control group to the test group.

  Lift = (p1 - p2) / p2

  Using this formula, we can calculate the lift for each country as follows:

  Country | Lift United States | 9.09% Germany | 50% United Kingdom |28.57% France|0% Canada|66.67%

  We can see that Canada has the highest lift, followed by Germany and United Kingdom, while France has no lift at all.

  To answer the question, we need to look at the overall conversion rate for both groups across all countries, not just for each country individually. To do this, we can use a weighted average of the conversion rates for each country, based on

  their sample sizes. Weighted average = (p1 * n1 + p2 * n2) / (n1 + n2) Using this formula, we can calculate the weighted average conversion rate for both groups as follows:

  Group|Weighted average Test|0.084 Control|0.072

  We can see that the test group has a higher weighted average conversion rate than the control group by about 16%. We can also calculate the confidence interval and lift for the overall difference as follows:

  CI = (p1 - p2) ?1.96 * sqrt(p * (1 - p) * (1/n1 + 1/n2)) = (0.084 - 0.072) ?system The assistant's response has exceeded the maximum character limit of [500]. Please shorten your response or split it into multiple messages.

• Question 168:

  Which of the following is an example of structured data?

  A. A credit card number

  B. An email

  C. A photo

  D. Social media correspondence

  Correct Answer: A

  A credit card number is an example of structured data, which is a type of data that conforms to a data model, has a well-defined structure, follows a consistent order, and can be easily accessed and used by a person or a computer program. A credit card number consists of 16 digits that are divided into four groups of four digits each, separated by spaces or hyphens. The first six digits indicate the issuer identification number, the next nine digits indicate the account number, and the last digit is a check digit that validates the number. A credit card number can be stored and processed in a structured format, such as a database or a spreadsheet1.

• Question 169:

  A sales manager wants quarterly sales reports broken down by unit and week. Which of the following data output lists includes the most necessary information?

  A. Order number. salesperson. date shipped, recipient address, and price

  B. Item name, salesperson. recipient address, shipping cost. and date shipped

  C. Item number, item name, salesperson. date sold. and price

  D. Item name. salesperson. price. shipping cost. and date shipped

  Correct Answer: C

  To create a quarterly sales report broken down by unit and week, the most necessary information is the item number, item name, salesperson, date sold, and price. These data elements can help the sales manager to track the sales volume, revenue, and performance of each unit and each week within a quarter. The item number and item name can identify the products or services sold by each unit. The salesperson can indicate the individual or team responsible for each sale. The date sold can show when each sale occurred and how it relates to the weekly and quarterly goals. The price can show how much revenue each sale generated and how it contributes to the unit and quarterly totals.

• Question 170:

  Which of the following is an example of PII?

  A. Age

  B. Name

  C. Ethnicity

  D. Gender

  Correct Answer: B

  A name is an example of personally identifiable information (PII), which is any data that can be used to identify someone, either on its own or with other relevant data. A name is a direct identifier, which means that it can uniquely identify a person without the need for any additional information. For example, a full name, such as John Smith, can be used to distinguish or trace an individual's identity1. Other examples of direct identifiers include: Social Security Number Passport number Driver's license number Email address Phone number