A data analyst is joining two tables with different content and one common field. Which of the following should the analyst do to most efficiently meet this requirement?
Correct Answer:
A
This question falls under theData Acquisition and Preparationdomain, focusing on combining data from multiple tables. The tables have different content but share a common field, indicating a join operation.
✑ Match the records of the related columns and merge the tables (Option A): This
describes a join operation, where records are matched on the common field (e.g.,
a key like Customer_ID) and the tables are merged, which is the most efficient method.
✑ Create a cluster to facilitate data integration between the tables (Option B):
Clustering is a machine learning technique, not a method for joining tables.
✑ Explode both tables to identify unique values and reorder the fields in one table (Option C): Exploding is used in nested data (e.g., JSON arrays), and this approach is overly complex and unnecessary.
✑ Append the values of the matching columns and concatenate the other data fields (Option D): Appending stacks tables vertically, and concatenation applies to text, neither of which is appropriate for joining tables with a common field.
The DA0-002 Data Acquisition and Preparation domain includes "executing data manipulation," such as joining tables using a common field.
Reference: CompTIA Data+ DA0-002 Draft Exam Objectives, Domain 2.0 Data Acquisition and Preparation.
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A data analyst needs to identify outliers from a given dataset. Which of the following visualizations is the best way to identify outliers?
Correct Answer:
A
This question falls under theVisualization and Reportingdomain, focusing on selecting the appropriate visualization to identify outliers in a dataset.
✑ Box plot (Option A): A box plot displays the distribution of data, including the
median, quartiles, and outliers (data points beyond the whiskers), making it the best choice for identifying outliers.
✑ Scatter plot (Option B): A scatter plot shows relationships between two variables,
and while outliers may be visible, it??s not specifically designed for outlier detection.
✑ Gantt chart (Option C): Gantt charts are for project scheduling, not suitable for outlier identification.
✑ Waterfall chart (Option D): Waterfall charts show cumulative changes (e.g., financial contributions), not designed for outlier detection.
The DA0-002 Visualization and Reporting domain emphasizes "translating business requirements to form the appropriate visualization," and a box plot is the standard visualization for identifying outliers.
Reference: CompTIA Data+ DA0-002 Draft Exam Objectives, Domain 4.0 Visualization and Reporting.
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A data analyst receives an email from the IT department about renewing the company password, and the analyst follows the password reset link as required. Later in the week, the analyst receives the following notification when running a recurring analysis that connects to the database:
Log-in failed for user ??
Which of the following is most likely the reason for this issue?
Correct Answer:
C
This question falls under theData Governancedomain, focusing on data access and security troubleshooting. The analyst reset their password, but the recurring analysis failed to log in, indicating a mismatch.
✑ The company changed its database authentication method (Option A): This would
affect all users, not just the analyst, and there??s no indication of a broader change.
✑ The password expiration process locked the account (Option B): The analyst reset the password as required, so the account isn??t likely locked due to expiration.
✑ The analyst did not change the password used to launch the report (Option C): Recurring analyses often use stored credentials. If the analyst updated their password but didn??t update the stored credentials for the analysis, the login would fail, making this the most likely reason.
✑ The company is experiencing issues with password replication (Option D): This is possible but less likely without evidence of broader system issues.
The DA0-002 Data Governance domain includes "data privacy concepts," and ensuring stored credentials match updated passwords is a common issue in recurring analyses. Reference: CompTIA Data+ DA0-002 Draft Exam Objectives, Domain 5.0 Data Governance.
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Which of the following is a NoSQL database?
Correct Answer:
D
This question falls under theData Concepts and Environmentsdomain, focusing on types of databases. The task is to identify a NoSQL database among the options.
✑ PostgreSQL (Option A): PostgreSQL is a relational (SQL) database, not NoSQL.
✑ MySQL (Option B): MySQL is a relational (SQL) database, not NoSQL.
✑ Oracle (Option C): Oracle Database is a relational (SQL) database, not NoSQL.
✑ MongoDB (Option D): MongoDB is a NoSQL database that uses a document- based model, storing data in JSON-like structures, making it the correct choice.
The DA0-002 Data Concepts and Environments domain includes understanding "different types of databases and data repositories," and MongoDB is a well-known NoSQL database.
Reference: CompTIA Data+ DA0-002 Draft Exam Objectives, Domain 1.0 Data Concepts and Environments.
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A recent server migration applied an update to dataset naming conventions. Multiple users are now reporting stale information in an existing dashboard. The date in the dataset confirms a successful data refresh. Which of the following should a data analyst do first?
Correct Answer:
A
This question falls under theData Governancedomain, focusing on troubleshooting data freshness issues in dashboards. The dashboard shows stale data despite a successful refresh, and the server migration updated naming conventions, suggesting a potential mismatch.
✑ Confirm the dashboard is pointed to the newest dataset (Option A): The server
migration updated dataset naming conventions, so the dashboard might still be pointing to an old dataset name, causing stale data. Confirming the dataset connection is the first step.
✑ Filter the data in the dashboard (Option B): Filtering might adjust the view but
doesn??t address the root cause of stale data.
✑ Escalate user permissions on the server (Option C): Permissions issues would likely prevent access, not cause stale data, especially since the dataset refreshed successfully.
✑ Verify that the dashboard subscription is not expired (Option D): An expired subscription might prevent access, but the dashboard is accessible, just showing stale data.
The DA0-002 Data Governance domain includes "data quality control concepts," such as ensuring dashboards connect to the correct, updated datasets after changes like server migrations.
Reference: CompTIA Data+ DA0-002 Draft Exam Objectives, Domain 5.0 Data Governance.
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