CompTIA CompTIA Certifications DA0-001 Questions & Answers

• Question 81:

  You have two databases tables that you would like to join together using a foreign key relationship.

  What term best describes this action?

  A. Blending.

  B. Appending.

  C. Mixing.

  D. Merging.

  Correct Answer: D

  Data merging is the process of combining two or more data sets into a single data set. Most often, this process is necessary when you have raw data stored in multiple files, worksheets, or data tables, that you want to analyze all in one go.

• Question 82:

  Exhibit.

  

  Which of the following logical statements results in Table B?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: D

  Explanation: The logical statement that results in Table B is Option D. Option D is a logical statement that uses the AND operator to combine two conditions: Name = "Tom" and Region = "BC". The AND operator returns true only if both

  conditions are true, otherwise it returns false. Therefore, Option D will select only the rows from Table A that satisfy both conditions, which are rows 4, 5, 6, and 7. These rows form Table B, as shown below:

  Name | Gender flag | Level | College | Code | Region Tom | Male | Elementary | A | BC | BC Kim | Female | Elementary | A | BC | BC Pat | Female | Elementary | A | BC | BC Ben | Male | Elementary | A | BC | BC

  The other options are not correct, as they use different logical operators or conditions that do not result in Table B. Option A uses the OR operator, which returns true if either condition is true, or both. Option A will select all the rows from

  Table A except row 3, which does not match either condition. Option B uses the NOT operator, which returns the opposite of the condition. Option B will select all the rows from Table A except rows 4, 5, 6, and 7, which match the condition.

  Option C uses a different condition, Region = "ON", which does not match any row in Table A. Option C will select no rows from Table A.

  Reference: [SQL Logical Operators - W3Schools]

• Question 83:

  Which of the following are reasons to create and maintain a data dictionary? (Choose two.)

  A. To improve data acquisition

  B. To remember specifics about data fields

  C. To specify user groups for databases

  D. To provide continuity through personnel turnover

  E. To confine breaches of PHI data

  F. To reduce processing power requirements

  Correct Answer: BD

  A data dictionary is a collection of metadata that describes the data elements in a database or dataset. It can help improve data acquisition by providing information about the data sources, formats, quality, and usage. It can also help remember specifics about data fields, such as their names, definitions, types, sizes, and relationships. Therefore, options B and D are correct.

  Option A is incorrect because it is not a reason to create and maintain a data dictionary, but a benefit of doing so.

  Option C is incorrect because specifying user groups for databases is not a function of a data dictionary, but a function of a database management system or a security policy.

  Option E is incorrect because confining breaches of PHI data is not a function of a data dictionary, but a function of a data protection or encryption system. Option F is incorrect because reducing processing power requirements is not a function of a data dictionary, but a function of a data compression or optimization system.

• Question 84:

  Given the following data: Which of the following BEST describes the data set?

  

  A. There is data bias.

  B. The data is incomplete.

  C. The data is inconsistent.

  D. The data is outliers.

  Correct Answer: C

  Explanation: This is because inconsistency is a type of data quality issue that occurs when the data does not follow a common format, structure, or rule across different sources or systems, which can affect the efficiency and performance of the analysis or process. Inconsistency can be caused by having different spellings, punctuations, capitalizations, or abbreviations for the same or similar values in a data set, such as "M", "m", "Male", or "male" for gender in this case. Inconsistency can be eliminated or reduced by using data cleansing techniques, such as standardizing or normalizing the data values. The other options are not correct descriptions of the data set. Here is why:

  Data bias is a type of data quality issue that occurs when the data is not representative or proportional of the population or the parameter, which can affect the validity and reliability of the analysis or process. Data bias can be caused by having a sample that is too small, too large, or too skewed for the population or the parameter, such as having only male customers for a product that targets both genders in this case. Data bias can be eliminated or reduced by using sampling techniques, such as stratified or cluster sampling. The data is incomplete is a type of data quality issue that occurs when the data is absent or missing in a data set, which can affect the accuracy and reliability of the analysis or process. The data is incomplete can be caused by various factors, such as human error, system error, or non-response. The data is incomplete can be addressed by using various methods, such as replacing or imputing the missing values with some reasonable estimates, such as mean, median, mode, or regression. The data is outliers is a type of data quality issue that occurs when the data has values that are unusually high or low compared to the rest of the data set, which can affect the quality and validity of the analysis or process. The data is outliers can be caused by various factors, such as measurement error, natural variation, or extreme events. The data is outliers can be addressed by using various methods, such as removing or filtering out the outliers, or using robust statistics that are less sensitive to outliers, such as median, interquartile range, or box plot.

• Question 85:

  A data analyst for a media company needs to determine the most popular movie genre. Given the table below:

  

  Which of the following must be done to the Genre column before this task can be completed?

  A. Append

  B. Merge

  C. Concatenate

  D. Delimit

  Correct Answer: D

  Explanation: Delimiting is the process of splitting a column of data into multiple columns based on a separator or delimiter character. Delimiting can help separate data that is combined or concatenated in one column into distinct values or categories. For example, if a column contains text values that are separated by commas, such as "Comedy, Suspense", delimiting can split this column into two columns, one for "Comedy" and one for "Suspense". Delimiting is different from other options, such as appending, merging, or concatenating, which are methods of combining or joining data from multiple columns or sources. In this case, the data analyst needs to determine the most popular movie genre based on the Genre column in the table. However, this column contains multiple genres for each movie, separated by commas. Therefore, the data analyst must delimit this column before this task can be completed. Therefore, the correct answer is D. References: Split text into different columns with functions - Office Support, How to Split Text in Excel (Using Formulas and Split Function)

• Question 86:

  A company's human resources department has asked a data analyst to categorize the income of all employees into five salary bands:

  

  Which of the following types of functions would be the most appropriate to use?

  A. Statistical

  B. Aggregate

  C. Logical

  D. Mathematical

  Correct Answer: C

  Short explanation: Logical functions are the most appropriate to use for categorizing data into bands, because they allow the data analyst to apply conditional statements and criteria to the data values. For example, the IF function can be used to assign a band name based on whether a value meets a certain condition or not. Other logical functions that can be useful for categorizing data are AND, OR, NOT, and IFERROR12

• Question 87:

  A sales director has requested a report for individual team members within the division be developed. The director would like the report to be shared with all team members, but individual team members should not be identifiable within the report Which of the following access requirements would support the director's needs?

  A. Create an acceptable use policy for the sales data.

  B. Release the report as user-group-based access and include data masking.

  C. Get a data use agreement from the individual team members.

  D. Provide the report based on role and include data encryption.

  Correct Answer: B

• Question 88:

  Which of the following BEST describes standard deviation?

  A. A measure that is used to establish a relationship between two variables

  B. A measure of how data is distributed

  C. A measure of the amount of dispersion of a set of values

  D. A measure that is used to find the significant difference between variables

  Correct Answer: C

  Explanation: A measure of the amount of dispersion of a set of values. This is because standard deviation is a type of statistical measure that quantifies how much the values in a data set vary or deviate from the mean or the average of the

  data set. Standard deviation can be used to describe the spread or the distribution of the data, as well as to identify any outliers or extreme values in the data. For example, a low standard deviation indicates that the values are close to the

  mean, while a high standard deviation indicates that the values are far from the mean. The other options are not correct descriptions of standard deviation.

  Here is why:

  A measure that is used to establish a relationship between two variables is not a correct description of standard deviation, but rather a description of correlation or regression, which are types of statistical measures that quantify how two

  variables are related or associated with each other. Correlation or regression can be used to test or model the dependence or the influence of one variable on another variable, as well as to predict or estimate the value of one variable based

  on the value of another variable.

  A measure of how data is distributed is not a correct description of standard deviation, but rather a description of frequency or probability, which are types of statistical measures that quantify how often or how likely a value or an event occurs

  in a data set. Frequency or probability can be used to describe the occurrence or the chance of the data, as well as to compare or contrast different categories or groups of the data.

  A measure that is used to find the significant difference between variables is not a correct description of standard deviation, but rather a description of hypothesis testing or inferential statistics, which are types of statistical methods that use

  sample data to make generalizations or conclusions about a population or a parameter. Hypothesis testing or inferential statistics can be used to test or verify a claim or an assumption about the data, as well as to measure the confidence or

  the error of the estimation.

• Question 89:

  An analyst is building a new dashboard for a user. After an initial conversation with the user. the analyst created a mock-up of the dashboard. Which of the following best explains why the analyst created the mock-up?

  A. To identify the dimensions and measures

  B. To send to the client after deploying the dashboard to production

  C. To confirm important details before dashboard development begins

  D. To receive client approval for the final dashboard design

  Correct Answer: C

  Explanation: Answer: C. To confirm important details before dashboard development begins.

  A dashboard mockup is a prototype of a finished dashboard directly in the product. It is a way to visualize the layout, design, and functionality of the dashboard before it is built with real data and code. A dashboard mockup can help the

  analyst to confirm important details with the user, such as the business objectives, the key performance indicators, the data sources, the filters, the charts, and the interactivity. By creating a dashboard mockup, the analyst can get immediate

  feedback and validation from the user, and avoid wasting time and resources on developing a dashboard that does not meet the user's expectations or needs1.

• Question 90:

  Consider this dataset showing the retirement age of 11 people, in whole years:

  54, 54, 54, 55, 56, 57, 57, 58, 58, 60, 60

  This tables show a simple frequency distribution of the retirement age data.

  

  A. 56

  B. 55

  C. 57

  D. 54

  Correct Answer: D

  A measure of central tendency (also referred to as measures of centre or central location) is a summary measure that attempts to describe a whole set of data with a single value that represents the middle or centre of its distribution. There

  are three main measures of central tendency: the mode, the median and the mean. Each of these measures describes a different indication of the typical or central value in the distribution.

  What is the mode?

  The mode is the most commonly occurring value in a distribution. The most commonly occurring value is 54, therefore the mode of this distribution is 54 years.