DA0-002 Practice Test 46 — 15 Questions

Question 1

A marketing team runs an A/B test comparing two webpage designs. The null hypothesis states there is no difference in conversion rates. The p-value is 0.08 at α=0.05. Which is the correct interpretation?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

There is insufficient evidence to conclude a difference between the designs.. Since p > α, we fail to reject the null hypothesis, meaning no statistically significant difference was found.

Answer

The null hypothesis is rejected, indicating the designs are different.

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The alternative hypothesis is accepted, showing the new design is better.

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There is a statistically significant difference between the designs.

Question 2

To consolidate data from multiple operational databases into a central repository for reporting, a company decides to transform data before loading it into the target system. Which data integration approach is being used?

Accepted Answer

ETL (Extract, Transform, Load). The scenario describes transforming data before loading it into the target system, which is the defining characteristic of ETL (Extract, Transform, Load). In ETL, data is extracted from source systems, transformed in a staging area (e.g., cleaning, aggregating, joining), and then loaded into the central repository. This approach is commonly used when the target system (e.g., a data warehouse) requires pre-processed, high-quality data for reporting.

Answer

Data virtualization

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Change data capture

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ELT (Extract, Load, Transform)

Question 3

A database has a table 'Orders' with columns OrderID (PK), CustomerID, OrderDate, and a table 'OrderDetails' with OrderID (FK), ProductID, Quantity. To ensure that every OrderID in OrderDetails exists in Orders, which integrity constraint is enforced?

Accepted Answer

Referential integrity. Referential integrity, enforced via a foreign key constraint, ensures that values in the foreign key column (OrderID in OrderDetails) match values in the primary key column of the referenced table (Orders).

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Entity integrity

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Domain integrity

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User-defined integrity

Question 4

A company wants to share a dataset with external partners via an API. Which API type is typically used for web services and uses XML or JSON for messaging?

Accepted Answer

REST API. REST APIs commonly use JSON or XML for messaging, making them a standard choice for data sharing over the web.

Answer

GraphQL API

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SOAP API

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WebSocket API

Question 5

A database administrator wants to ensure that every value in a column matches values in a primary key column of another table. Which constraint enforces this rule?

Accepted Answer

Foreign key. A foreign key constraint ensures referential integrity by requiring that values in a column match values in the primary key of another table.

Answer

Unique constraint

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Primary key

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Check constraint

Question 6

Which of the following is an example of unstructured data?

Accepted Answer

An image file. Unstructured data has no predefined schema. Images are a classic example of unstructured data.

Answer

A JSON file

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A relational database table

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A CSV file with rows and columns

Question 7

Which of the following is a characteristic of a NoSQL document database like MongoDB?

Accepted Answer

Schema-flexible, JSON-like documents. Document databases store data in flexible, JSON-like documents, allowing schema variability.

Answer

Data stored in tables with rows and columns

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Strict schema enforcement

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Support for ACID transactions across multiple documents

Question 8

A business analyst creates a one-time report to analyze customer churn for a special project. Which report type is being used?

Accepted Answer

Ad hoc report. A one-time, custom query for a specific purpose is an ad hoc report.

Answer

Scheduled report

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Self-service report

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Analytical report

Question 9

Which THREE of the following are NoSQL database types?

Accepted Answer

Document. Document databases, such as MongoDB, store data in flexible, JSON-like documents (BSON in MongoDB's case). This allows for nested structures and schema-less designs, making them a core NoSQL category distinct from relational models.

Answer

Hierarchical

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Relational

Question 10

A data analyst is creating a dashboard for a retail company. Which TWO of the following are considered Key Performance Indicators (KPIs) tied to strategic objectives?

Accepted Answer

Year-over-year revenue growth. KPIs are tied to strategic goals; revenue growth and customer retention align with high-level business strategy.

Answer

Average handle time per call

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Number of products in inventory

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Daily number of customer service calls

Question 11

A dashboard designer wants to ensure that the most important metric, such as total revenue, is prominently displayed at the top left. Which dashboard design principle is being applied?

Accepted Answer

Visual hierarchy. Visual hierarchy arranges elements by importance, typically with key metrics at the top or top-left.

Answer

Consistent color coding

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Appropriate precision

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Data-ink ratio

Question 12

A data analyst is building a dashboard in Tableau and wants to allow users to select a specific product category and have all charts on the dashboard filter to that category. Which Tableau feature should be used?

Accepted Answer

Dashboard action. Dashboard actions in Tableau enable interactivity such as filtering across sheets based on user clicks.

Answer

Calculated field

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LOD expression

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Parameter

Question 13

Which chart type is best for showing the sales pipeline from leads to closed deals, illustrating how many prospects drop off at each stage?

Accepted Answer

Funnel chart. A funnel chart is specifically designed to show conversion or drop-off rates in a pipeline.

Answer

Treemap

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Waterfall chart

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Stacked bar chart

Question 14

A data analyst is building a narrative around a quarterly sales decline. The story should follow a narrative arc. Which THREE elements should be included in the story?

Accepted Answer

Resolution: By diversifying suppliers, sales recovered in November.. A narrative arc in data storytelling typically includes situation (context), complication (problem), and resolution (recommendation or action).

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Random color scheme for every chart

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Detailed description of each product's sales breakdown

Question 15

A data analyst in a healthcare organization needs to visualize patient wait times across different departments. The data includes department names (categorical), wait times in minutes (continuous), and time of day. Which THREE chart types could be effectively used to explore this data?

Accepted Answer

Scatter plot. Box plots show distribution and outliers; scatter plots can show wait time vs. time of day; heat maps can show average wait time by department and time period. Histograms show distribution of a single variable, funnel charts are for pipelines.

Answer

Funnel chart

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Histogram