WGU D487 OA ACTUAL EXAM 150 QUESTIONS AND CORRECT
ANSWERS WITH DETAILED RATIONALES 2026 LATEST VERSION|
ALREADY GRADED A+
This set of 150 practice questions covers the foundational concepts of data analytics,
including data management, SQL queries, Python for analytics, data visualization, descriptive
and inferential statistics, and types of analytics (descriptive, diagnostic, predictive, and
prescriptive). The questions are intermixed across topics to simulate the style of the WGU
D487 Objective Assessment (OA). Each question includes the correct answer marked in red
and a rationale explaining why the answer is correct, helping students understand key
concepts and apply analytical thinking in real-world data scenarios. This resource is designed
to reinforce understanding, improve retention, and build confidence for exam readiness
1. Which of the following best describes data analytics?
A. The process of storing raw data
B. The process of examining data to draw insights
C. The process of designing databases
D. The process of encrypting data
Rationale: Data analytics involves inspecting, cleaning, and modeling data to discover useful
information.
2. Which type of data visualization is best for showing trends over time?
A. Pie chart
B. Line chart
C. Bar chart
D. Scatter plot
Rationale: Line charts are ideal for time series data to show trends.
3. Which statistical measure represents the middle value of a dataset?
A. Mean
B. Median
C. Mode
D. Range
Rationale: The median is the middle value when data is ordered.
,4. Which of the following is an example of structured data?
A. Excel spreadsheet with rows and columns
B. Audio recording
C. PDF document
D. Video file
Rationale: Structured data follows a predefined schema, like tables in Excel.
5. Which chart is most appropriate for comparing proportions of a whole?
A. Scatter plot
B. Line chart
C. Pie chart
D. Histogram
Rationale: Pie charts show percentages of a total.
6. Which of the following best describes a data warehouse?
A. Transactional database for daily operations
B. Centralized repository optimized for analytics
C. NoSQL document store
D. File storage system
Rationale: Data warehouses store integrated data for reporting and analytics.
7. Which of the following is an example of descriptive analytics?
A. Predicting sales for next year
B. Summarizing past sales data
C. Recommending products
D. Identifying causal relationships
Rationale: Descriptive analytics explains what has happened.
8. Which of the following is a type of inferential statistic?
A. Mean
B. Standard deviation
C. Hypothesis testing
D. Median
Rationale: Inferential statistics make predictions or draw conclusions from a sample.
,9. Which SQL clause is used to select specific columns?
A. SELECT
B. INSERT
C. UPDATE
D. DELETE
Rationale: SELECT specifies which columns to retrieve.
10. Which type of data is continuous and measurable?
A. Categorical
B. Quantitative
C. Ordinal
D. Nominal
Rationale: Quantitative data is numeric and can be measured.
11. Which visualization shows the distribution of a dataset?
A. Histogram
B. Line chart
C. Pie chart
D. Scatter plot
Rationale: Histograms group data into bins to show frequency distribution.
12. What is the primary purpose of ETL (Extract, Transform, Load) in analytics?
A. To create visualizations
B. To process and prepare data for analysis
C. To encrypt sensitive data
D. To generate hypotheses
Rationale: ETL pipelines extract data from sources, transform it, and load it into a database or
warehouse.
13. Which of the following best describes predictive analytics?
A. Describing historical trends
B. Forecasting future outcomes
C. Cleaning data
D. Storing large datasets
Rationale: Predictive analytics uses data and models to forecast future events.
, 14. Which measure indicates how spread out the data is?
A. Mean
B. Variance
C. Mode
D. Median
Rationale: Variance quantifies the dispersion of data points.
15. Which of the following is a common data cleaning task?
A. Removing duplicates
B. Creating dashboards
C. Running predictive models
D. Loading data
Rationale: Cleaning ensures accurate analysis by handling missing, incorrect, or redundant data.
16. Which visualization is best for showing correlation between two variables?
A. Histogram
B. Scatter plot
C. Pie chart
D. Line chart
Rationale: Scatter plots reveal relationships and patterns between variables.
17. Which measure of central tendency is most affected by extreme values?
A. Median
B. Mode
C. Mean
D. Range
Rationale: Mean is sensitive to outliers, unlike median or mode.
18. Which type of analytics identifies patterns or relationships in data?
A. Descriptive
B. Diagnostic
C. Predictive
D. Prescriptive
Rationale: Diagnostic analytics examines causes and patterns behind past outcomes.
ANSWERS WITH DETAILED RATIONALES 2026 LATEST VERSION|
ALREADY GRADED A+
This set of 150 practice questions covers the foundational concepts of data analytics,
including data management, SQL queries, Python for analytics, data visualization, descriptive
and inferential statistics, and types of analytics (descriptive, diagnostic, predictive, and
prescriptive). The questions are intermixed across topics to simulate the style of the WGU
D487 Objective Assessment (OA). Each question includes the correct answer marked in red
and a rationale explaining why the answer is correct, helping students understand key
concepts and apply analytical thinking in real-world data scenarios. This resource is designed
to reinforce understanding, improve retention, and build confidence for exam readiness
1. Which of the following best describes data analytics?
A. The process of storing raw data
B. The process of examining data to draw insights
C. The process of designing databases
D. The process of encrypting data
Rationale: Data analytics involves inspecting, cleaning, and modeling data to discover useful
information.
2. Which type of data visualization is best for showing trends over time?
A. Pie chart
B. Line chart
C. Bar chart
D. Scatter plot
Rationale: Line charts are ideal for time series data to show trends.
3. Which statistical measure represents the middle value of a dataset?
A. Mean
B. Median
C. Mode
D. Range
Rationale: The median is the middle value when data is ordered.
,4. Which of the following is an example of structured data?
A. Excel spreadsheet with rows and columns
B. Audio recording
C. PDF document
D. Video file
Rationale: Structured data follows a predefined schema, like tables in Excel.
5. Which chart is most appropriate for comparing proportions of a whole?
A. Scatter plot
B. Line chart
C. Pie chart
D. Histogram
Rationale: Pie charts show percentages of a total.
6. Which of the following best describes a data warehouse?
A. Transactional database for daily operations
B. Centralized repository optimized for analytics
C. NoSQL document store
D. File storage system
Rationale: Data warehouses store integrated data for reporting and analytics.
7. Which of the following is an example of descriptive analytics?
A. Predicting sales for next year
B. Summarizing past sales data
C. Recommending products
D. Identifying causal relationships
Rationale: Descriptive analytics explains what has happened.
8. Which of the following is a type of inferential statistic?
A. Mean
B. Standard deviation
C. Hypothesis testing
D. Median
Rationale: Inferential statistics make predictions or draw conclusions from a sample.
,9. Which SQL clause is used to select specific columns?
A. SELECT
B. INSERT
C. UPDATE
D. DELETE
Rationale: SELECT specifies which columns to retrieve.
10. Which type of data is continuous and measurable?
A. Categorical
B. Quantitative
C. Ordinal
D. Nominal
Rationale: Quantitative data is numeric and can be measured.
11. Which visualization shows the distribution of a dataset?
A. Histogram
B. Line chart
C. Pie chart
D. Scatter plot
Rationale: Histograms group data into bins to show frequency distribution.
12. What is the primary purpose of ETL (Extract, Transform, Load) in analytics?
A. To create visualizations
B. To process and prepare data for analysis
C. To encrypt sensitive data
D. To generate hypotheses
Rationale: ETL pipelines extract data from sources, transform it, and load it into a database or
warehouse.
13. Which of the following best describes predictive analytics?
A. Describing historical trends
B. Forecasting future outcomes
C. Cleaning data
D. Storing large datasets
Rationale: Predictive analytics uses data and models to forecast future events.
, 14. Which measure indicates how spread out the data is?
A. Mean
B. Variance
C. Mode
D. Median
Rationale: Variance quantifies the dispersion of data points.
15. Which of the following is a common data cleaning task?
A. Removing duplicates
B. Creating dashboards
C. Running predictive models
D. Loading data
Rationale: Cleaning ensures accurate analysis by handling missing, incorrect, or redundant data.
16. Which visualization is best for showing correlation between two variables?
A. Histogram
B. Scatter plot
C. Pie chart
D. Line chart
Rationale: Scatter plots reveal relationships and patterns between variables.
17. Which measure of central tendency is most affected by extreme values?
A. Median
B. Mode
C. Mean
D. Range
Rationale: Mean is sensitive to outliers, unlike median or mode.
18. Which type of analytics identifies patterns or relationships in data?
A. Descriptive
B. Diagnostic
C. Predictive
D. Prescriptive
Rationale: Diagnostic analytics examines causes and patterns behind past outcomes.
