Google Data Analytics Professional Certificate Exam Testbank
| All Questions And Answers 2026/2027 | Verified Answers
Plus Rationales | Graded Q&A Comprehensive Study Guide |
Verified Latest 2027
1. A junior data analyst is tasked with understanding business objectives for a new retail
campaign. Which phase of the data analysis life cycle does this activity primarily fall
under?
A. Clean
B. Ask
C. Share
D. Act
Answer: B
The Ask phase involves defining the problem, understanding stakeholder expectations, and
identifying the core business objectives before diving into data collection or analysis.
2. An analyst is working with a massive customer transaction dataset and needs to find the
total revenue generated by each product category. Which SQL aggregate function should
be combined with a GROUP BY clause to achieve this?
A. COUNT()
B. AVERAGE()
C. SUM()
D. MAXIMUM()
Answer: C
The SUM() function aggregates numerical values across specified groups, making it the
correct choice for calculating cumulative totals like revenue per category.
3. During data cleaning in a spreadsheet, you notice that a column containing customer
ages has several negative values due to a data entry glitch. What type of data quality issue
does this represent?
A. Missing data
B. Out-of-range or invalid data
C. Duplicate records
D. Structural formatting inconsistency
Answer: B
,A negative age is physically impossible, representing invalid or out-of-range data that
violates logical business constraints and requires cleaning.
4. A data analyst is preparing a data visualization for executive stakeholders who have
limited time. Which chart type is best suited for showing trends over a continuous time
period, such as monthly sales growth over three years?
A. Pie chart
B. Scatter plot
C. Line chart
D. Bar chart
Answer: C
Line charts are specifically designed to display trends, changes, and trajectories over
chronological time periods effectively.
5. In R programming, you want to filter a dataframe named sales_data to include only
rows where the region column equals "North". Which syntax is correct using tidyverse
functions?
A. sales_data %>% filter(region == "North")
B. filter(sales_data, region = "North")
C. sales_data %>% select(region == "North")
D. subset(sales_data, region <> "North")
Answer: A
The pipe operator %>% combined with the filter() function and the double equals comparison
operator == is the standard tidyverse syntax for subsetting rows in R.
6. A data professional is evaluating potential bias in a dataset collected from an online
survey about smartphone usage. The survey was distributed exclusively via a mobile
gaming app. What type of sampling or selection bias is most likely present?
A. Historical bias
B. Observer bias
C. Sampling or coverage bias
D. Interpretation bias
Answer: C
Coverage bias occurs when the sample population does not adequately represent the target
population because certain groups are systematically excluded or overrepresented.
,7. You need to combine two SQL tables—customers and orders—so that you retrieve all
customer records along with any matching order records, but you want to keep all
customers even if they have never placed an order. Which join should you use?
A. INNER JOIN
B. LEFT JOIN
C. RIGHT JOIN
D. FULL OUTER JOIN
Answer: B
A LEFT JOIN returns all records from the left table (customers) and matched records from the
right table (orders), returning nulls for unmatched customer rows.
8. An analyst wants to test whether a new website layout increases user checkout rates
compared to the legacy layout. They set up a controlled experiment tracking two user
groups. What type of analysis is being conducted?
A. Descriptive analysis
B. Diagnostic analysis
C. Predictive analysis
D. A/B testing (experimentation)
Answer: D
A/B testing is an experimental methodology used to compare two versions of a variable
against each other to determine which performs better.
9. When cleaning data in SQL, you want to remove leading and trailing white spaces from
a text column called customer_name. Which string function should you use?
A. LOWER()
B. TRIM()
C. LENGTH()
D. SUBSTR()
Answer: B
The TRIM() function removes leading and trailing spaces from text strings, ensuring data
consistency across text fields.
10. A stakeholder asks you to prove why website bounce rates spiked last month. Which
phase of the data analysis process addresses finding the underlying causes of past events?
A. Diagnostic analysis
B. Predictive analysis
, C. Prescriptive analysis
D. Descriptive analysis
Answer: A
Diagnostic analysis examines data to answer questions about why something happened by
investigating causes and correlations.
11. In Tableau or similar data visualization software, what is the primary purpose of
adding a filter to a dashboard?
A. To permanently delete unwanted data rows from the underlying database
B. To allow users to subset, focus on, and interact with specific subsets of data dynamically
C. To encrypt sensitive financial figures automatically
D. To convert text strings into numerical arrays
Answer: B
Filters in data visualization tools enable dynamic interactivity, allowing viewers to isolate
specific variables, dates, or regions of interest.
12. You are calculating summary statistics for a dataset containing employee salaries that
include a few extremely high executive payouts. Which measure of central tendency is most
resistant to these outliers?
A. Mean
B. Median
C. Sum
D. Standard deviation
Answer: B
The median represents the middle value in a sorted dataset and is not skewed by extreme
outliers or skewed distributions like the mean.
13. A data analyst uses the SQL query SELECT COUNT(DISTINCT customer_id) FROM
orders;. What does this query calculate?
A. The total number of orders placed across all customers
B. The total number of unique customers who placed orders
C. The average order value per customer
D. The maximum number of orders placed by a single customer
Answer: B
| All Questions And Answers 2026/2027 | Verified Answers
Plus Rationales | Graded Q&A Comprehensive Study Guide |
Verified Latest 2027
1. A junior data analyst is tasked with understanding business objectives for a new retail
campaign. Which phase of the data analysis life cycle does this activity primarily fall
under?
A. Clean
B. Ask
C. Share
D. Act
Answer: B
The Ask phase involves defining the problem, understanding stakeholder expectations, and
identifying the core business objectives before diving into data collection or analysis.
2. An analyst is working with a massive customer transaction dataset and needs to find the
total revenue generated by each product category. Which SQL aggregate function should
be combined with a GROUP BY clause to achieve this?
A. COUNT()
B. AVERAGE()
C. SUM()
D. MAXIMUM()
Answer: C
The SUM() function aggregates numerical values across specified groups, making it the
correct choice for calculating cumulative totals like revenue per category.
3. During data cleaning in a spreadsheet, you notice that a column containing customer
ages has several negative values due to a data entry glitch. What type of data quality issue
does this represent?
A. Missing data
B. Out-of-range or invalid data
C. Duplicate records
D. Structural formatting inconsistency
Answer: B
,A negative age is physically impossible, representing invalid or out-of-range data that
violates logical business constraints and requires cleaning.
4. A data analyst is preparing a data visualization for executive stakeholders who have
limited time. Which chart type is best suited for showing trends over a continuous time
period, such as monthly sales growth over three years?
A. Pie chart
B. Scatter plot
C. Line chart
D. Bar chart
Answer: C
Line charts are specifically designed to display trends, changes, and trajectories over
chronological time periods effectively.
5. In R programming, you want to filter a dataframe named sales_data to include only
rows where the region column equals "North". Which syntax is correct using tidyverse
functions?
A. sales_data %>% filter(region == "North")
B. filter(sales_data, region = "North")
C. sales_data %>% select(region == "North")
D. subset(sales_data, region <> "North")
Answer: A
The pipe operator %>% combined with the filter() function and the double equals comparison
operator == is the standard tidyverse syntax for subsetting rows in R.
6. A data professional is evaluating potential bias in a dataset collected from an online
survey about smartphone usage. The survey was distributed exclusively via a mobile
gaming app. What type of sampling or selection bias is most likely present?
A. Historical bias
B. Observer bias
C. Sampling or coverage bias
D. Interpretation bias
Answer: C
Coverage bias occurs when the sample population does not adequately represent the target
population because certain groups are systematically excluded or overrepresented.
,7. You need to combine two SQL tables—customers and orders—so that you retrieve all
customer records along with any matching order records, but you want to keep all
customers even if they have never placed an order. Which join should you use?
A. INNER JOIN
B. LEFT JOIN
C. RIGHT JOIN
D. FULL OUTER JOIN
Answer: B
A LEFT JOIN returns all records from the left table (customers) and matched records from the
right table (orders), returning nulls for unmatched customer rows.
8. An analyst wants to test whether a new website layout increases user checkout rates
compared to the legacy layout. They set up a controlled experiment tracking two user
groups. What type of analysis is being conducted?
A. Descriptive analysis
B. Diagnostic analysis
C. Predictive analysis
D. A/B testing (experimentation)
Answer: D
A/B testing is an experimental methodology used to compare two versions of a variable
against each other to determine which performs better.
9. When cleaning data in SQL, you want to remove leading and trailing white spaces from
a text column called customer_name. Which string function should you use?
A. LOWER()
B. TRIM()
C. LENGTH()
D. SUBSTR()
Answer: B
The TRIM() function removes leading and trailing spaces from text strings, ensuring data
consistency across text fields.
10. A stakeholder asks you to prove why website bounce rates spiked last month. Which
phase of the data analysis process addresses finding the underlying causes of past events?
A. Diagnostic analysis
B. Predictive analysis
, C. Prescriptive analysis
D. Descriptive analysis
Answer: A
Diagnostic analysis examines data to answer questions about why something happened by
investigating causes and correlations.
11. In Tableau or similar data visualization software, what is the primary purpose of
adding a filter to a dashboard?
A. To permanently delete unwanted data rows from the underlying database
B. To allow users to subset, focus on, and interact with specific subsets of data dynamically
C. To encrypt sensitive financial figures automatically
D. To convert text strings into numerical arrays
Answer: B
Filters in data visualization tools enable dynamic interactivity, allowing viewers to isolate
specific variables, dates, or regions of interest.
12. You are calculating summary statistics for a dataset containing employee salaries that
include a few extremely high executive payouts. Which measure of central tendency is most
resistant to these outliers?
A. Mean
B. Median
C. Sum
D. Standard deviation
Answer: B
The median represents the middle value in a sorted dataset and is not skewed by extreme
outliers or skewed distributions like the mean.
13. A data analyst uses the SQL query SELECT COUNT(DISTINCT customer_id) FROM
orders;. What does this query calculate?
A. The total number of orders placed across all customers
B. The total number of unique customers who placed orders
C. The average order value per customer
D. The maximum number of orders placed by a single customer
Answer: B
