DA0-002 Practice Exam 61 — 20 Questions

Question 1

A data analyst is building a dashboard that includes a filter for 'Region'. The dashboard also contains a table showing sales by product category. The analyst wants to ensure that when a user selects a region from the filter, the table updates to show only sales for that region. Which feature should the analyst configure?

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

Accepted Answer

Action filter. An action filter is the correct feature to enable cross-visual filtering. It allows a selection in one visual (the region filter) to dynamically filter another visual (the table). This creates an interactive dashboard where users can explore data by region without manually adjusting multiple filters.

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Calculated field

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Data blending

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Parameter

Question 2

A marketing analyst is building a dashboard that groups customers by the state listed in their billing address so the sales team can compare performance across regions. The analyst retrieves the raw address data stored in a single text column. Which data type classification best describes the state field as the analyst intends to use it?

Accepted Answer

Nominal. State names are categorical labels used to segment customers into groups, and there is no ranking or numeric distance between them. That makes the field nominal for this dashboard. Ordinal, interval, and ratio all require either an inherent order or numeric measurement properties that state labels do not have, so they cannot apply to this grouping task.

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Ordinal

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Ratio

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Interval

Question 3

A data analyst is profiling a dataset of customer orders. The 'order_date' column contains dates in various formats, including 'YYYY-MM-DD', 'DD/MM/YYYY', and 'MM-DD-YYYY'. The analyst needs to standardize these dates into a single format for time-series analysis. Which approach should the analyst take?

Accepted Answer

Use a regular expression to extract year, month, and day, then reconstruct the date in a standard format.. The dates are stored in multiple formats, so a one-size-fits-all parsing function will fail. Using regular expressions to extract the year, month, and day components allows the analyst to handle each pattern systematically and then reconstruct a standardized date. This method is robust and does not depend on locale settings.

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Sort the dates lexicographically and then apply a standard format.

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Apply a single date parsing function with a fixed format string.

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Convert the dates to Unix timestamps using a generic conversion function.

Question 4

A data analyst is building a predictive model to forecast customer churn. The dataset includes a categorical feature 'payment_method' with categories: credit card, debit card, PayPal, and bank transfer. The analyst decides to use one-hot encoding. After encoding, the analyst notices that the model's performance on the training set is excellent but poor on the test set. Which issue is most likely contributing to this problem?

Accepted Answer

The model is overfitting due to high dimensionality from one-hot encoding combined with a small dataset.. Overfitting is indicated by strong training performance and weak test performance. One-hot encoding expands the feature space, and with a small dataset, this can lead to a model that memorizes training noise. The other options do not directly explain overfitting: multicollinearity affects interpretation, data leakage would inflate both training and test scores, and payment methods are nominal so ordinality is irrelevant. Thus, high dimensionality from encoding is the most plausible cause.

Answer

The one-hot encoding caused data leakage from the test set into the training set.

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The one-hot encoding failed to capture the ordinal relationship among payment methods.

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The one-hot encoding introduced multicollinearity among the payment method dummy variables.

Question 5

A data analyst has built a dashboard that tracks monthly website traffic. The dashboard currently uses a line chart to show the trend of total visits over time. The marketing team now wants to see how each of four traffic sources (organic, paid, social, referral) contributes to the total each month, while still being able to see the overall trend. Which chart type best meets this requirement?

Accepted Answer

Stacked area chart. A stacked area chart is designed to show how multiple components contribute to a total over a continuous time period. It allows the viewer to see both the overall trend and the relative contribution of each traffic source. Other chart types either cannot show time trends or cannot show composition effectively.

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Scatter plot

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Pie chart

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Bar chart

Question 6

A data analyst is creating a dashboard for a hospital's emergency department. The dashboard must display the current wait time, the number of patients waiting, and the average wait time over the past 24 hours. The analyst wants to ensure that the most critical information is immediately visible to the charge nurse. Which design principle should the analyst apply?

Accepted Answer

Use a consistent color scheme and place the most important metric in the top-left corner with a larger font size.. The charge nurse needs to see the most critical information—current wait time—immediately. Applying visual hierarchy by placing that metric in the top-left corner with a larger font size ensures it is noticed first. A consistent color scheme aids quick interpretation without distraction, supporting rapid decision-making in a fast-paced environment.

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Place all metrics in a single table for easy comparison.

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Include detailed data labels on all charts to provide context.

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Use a variety of chart types to make the dashboard visually interesting.

Question 7

A data engineer is ingesting streaming data from a fleet of delivery vehicles. Each vehicle sends GPS coordinates, speed, and timestamp every second. The engineer needs to store this data for real-time dashboards and also retain it for long-term historical analysis. Which data storage approach best balances real-time access and cost-effective long-term retention?

Accepted Answer

Use a time-series database for recent data and archive to object storage. A time-series database handles high-velocity timestamped writes and enables fast real-time queries for dashboards. Archiving older data to object storage reduces cost while preserving durability for historical analysis. Row-based relational databases, key-value stores without indexes, and in-memory caches each fail to balance real-time performance with cost-effective long-term retention for streaming vehicle telemetry.

Answer

Store all data in a relational database with row-based storage

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Keep all data in memory using an in-memory cache

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Store all data in a key-value store with no secondary indexes

Question 8

A data analyst is analyzing a time series of monthly sales for a retail store. The analyst observes a repeating pattern every 12 months. Which component of the time series is the analyst observing?

Accepted Answer

Seasonality. Seasonality is the time series component that captures repeating patterns at fixed intervals, such as every 12 months in monthly data. The analyst's observation of a yearly repeating pattern in sales is a direct example of seasonality. Trend, cyclicality, and noise do not describe fixed-period repetitions. Therefore, seasonality is the correct component.

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Noise

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Trend

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Cyclicality

Question 9

A data analyst is integrating customer data from two source systems: a CRM and a billing system. The CRM uses a customer ID format of 'CUST-12345', while the billing system uses '12345'. The analyst needs to join records on customer ID. Which two steps are necessary to prepare the data for a successful join? (Choose two.)

Accepted Answer

Extract the numeric portion from the CRM customer ID to match the billing system format.. The necessary steps are to extract the numeric portion from the CRM ID and to ensure both ID fields share a consistent data type. These actions standardize the join key, allowing records to match correctly across the two systems. Without them, the join would fail due to format and type mismatches, leading to incomplete or incorrect integration.

Answer

Apply a hash function to both customer ID fields to anonymize them.

Answer

Sort both datasets by customer ID before joining.

Answer

Create a cross-reference table mapping CRM IDs to billing IDs.

Question 10

A marketing analyst is reviewing a dataset of campaign responses. The 'response' column contains values 'Yes', 'No', 'Y', 'N', 'yes', and 'no'. Before analysis, the analyst needs to count how many customers responded positively. Which data preparation step is most appropriate?

Accepted Answer

Standardize the values to 'Yes' and 'No' using case normalization and mapping.. The analyst should standardize the values to 'Yes' and 'No' by normalizing case and mapping abbreviations. This ensures all positive responses are consistently represented, enabling accurate counting and analysis. Without standardization, variations like 'Y' and 'yes' would be treated as separate categories, leading to incorrect insights.

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Convert the column to uppercase to make all values consistent.

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Filter out rows with 'Y' and 'N' because they are abbreviations.

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Create a new binary column where 'Yes' and 'Y' are 1, and all else 0.

Question 11

A junior data analyst at an e-commerce company wants to query a production customer table that contains email addresses and purchase history. Company policy states that analysts may access only the columns needed for their assigned task and must request elevated access for sensitive fields. Which data governance principle is the policy enforcing?

Accepted Answer

Least privilege. Least privilege restricts access to only what is required for a user's role and task. The policy lets the junior analyst query necessary columns while requiring an elevated request for sensitive fields like email addresses, which is a direct application of that principle. It reduces exposure of personal data without blocking legitimate analytical work.

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Data sovereignty

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Data archiving

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Data redundancy

Question 12

A data analyst is designing a dashboard that will be viewed on both desktop monitors and mobile devices. The dashboard contains several charts and KPI cards. Which design approach best ensures usability across these devices?

Accepted Answer

Implement a responsive layout that rearranges and resizes elements based on screen size. Implementing a responsive layout is the best approach because it dynamically adjusts the dashboard's elements to fit any screen size, ensuring that charts and KPIs are legible and interactive on both desktop and mobile. This avoids the pitfalls of horizontal scrolling, separate maintenance, and unreadable compact designs.

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Use small fonts and compact charts to fit more information on mobile screens

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Use a fixed-width layout with horizontal scrolling for mobile users

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Create two separate dashboards: one for desktop and one for mobile

Question 13

A data analyst is building a report that will be distributed as a PDF to stakeholders. The report includes a bar chart showing sales by region. The analyst wants to ensure that the chart is accessible to color-blind readers. Which action should the analyst take?

Accepted Answer

Add data labels to each bar and use a color palette that is distinguishable for common types of color blindness. To make a bar chart accessible for color-blind readers, the analyst should add data labels and use a colorblind-friendly palette. Data labels provide direct value readouts, while a carefully chosen palette ensures that colors are distinguishable for common types of color vision deficiency. This combination guarantees that the chart is interpretable by all stakeholders.

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Use a red-green color scheme to highlight high and low performers

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Convert the bar chart to a pie chart with a legend

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Use a monochromatic color scheme with varying shades of blue

Question 14

A data analyst at a hospital is building a report on patient readmissions. The analyst needs to combine the patient demographics table (which uses PatientID as the primary key) with the admissions table (which uses AdmissionID as the primary key and also contains PatientID as a foreign key). Which type of operation should the analyst use to combine these two tables?

Accepted Answer

Join. Combining two tables that share a common key, such as PatientID, requires a join operation. A join matches rows from both tables on the key and returns columns from both, enabling the analyst to see patient demographics alongside each admission. Other set operations like union or intersect do not align columns properly for this purpose.

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Aggregate

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Intersect

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Union

Question 15

An insurer's data governance team discovers that a legacy reporting pipeline transforms policy effective dates using a hard-coded time zone offset that was correct five years ago but is now wrong for a newly acquired business unit. The team must document where the defect originates, which downstream reports are affected, and how to prevent recurrence. Which governance capability is MOST directly suited to this investigation?

Accepted Answer

Data lineage, which maps source-to-target transformations and downstream dependencies across the pipeline. Lineage is the capability that records transformation logic and dependency chains, making it the right tool to locate the hard-coded offset and trace every downstream report affected by it. Profiling detects value anomalies without explaining logic, masking protects non-production data, and retention manages lifecycle duration. Only lineage ties the defect's origin to its consumers for impact assessment and regression planning.

Answer

Data masking, which obfuscates sensitive fields so non-production environments can be used safely

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Data retention scheduling, which automates archival and deletion of records past their required lifecycle

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Data profiling, which statistically summarizes column distributions to detect outliers and anomalies

Question 16

An analyst is profiling a newly acquired customer table and wants a quick summary of the central tendency and spread of the 'annual_income' column, which contains a few extreme outliers from data entry errors. Which combination of descriptive statistics is most appropriate to report the typical income while limiting the influence of those outliers?

Accepted Answer

Median and interquartile range. For skewed data with known outliers, robust statistics are preferred. The median resists extreme values and represents the middle of the distribution, while the interquartile range measures spread using the middle 50 percent of records. Mean and standard deviation, mode and range, and sum and count either amplify outlier influence or fail to describe central tendency and dispersion together.

Answer

Sum and count

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Mean and standard deviation

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Mode and range

Question 17

A data engineer is profiling a dataset of customer orders and notices that the 'order_date' column contains values in multiple formats: 'YYYY-MM-DD', 'MM/DD/YYYY', and 'DD-Mon-YYYY'. The column is currently stored as a string. Which action should the engineer take to ensure consistent date handling for analysis?

Accepted Answer

Parse each format and load the dates into a new column with a consistent DATE data type.. The engineer should parse each date format and load the values into a new column with a consistent DATE data type. This standardizes the data at the storage level, ensuring all analytical queries and tools interpret dates uniformly. It also allows the use of native date functions and avoids repeated conversion logic in every query.

Answer

Use a CASE statement to convert each format to a standard date type during queries.

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Replace all delimiters with hyphens to make the strings look uniform.

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Leave the column as string and rely on the BI tool to interpret the formats.

Question 18

A data analyst is examining a dataset of customer transactions and notices that the 'transaction_amount' column contains negative values. The analyst determines that these negative values represent refunds. Which data quality dimension is most directly relevant to this finding?

Accepted Answer

Validity. Validity is about whether data adheres to defined rules or constraints. Negative transaction amounts may be valid if refunds are permitted, but the analyst must verify that such values are allowed by business rules. Accuracy, completeness, and consistency do not directly address the conformity to rules. Thus, validity is the most relevant dimension when encountering unexpected negative values that might indicate either a data error or a legitimate business process.

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Consistency

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Accuracy

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Completeness

Question 19

A data analyst is preparing a dataset for a machine learning model and needs to handle missing values in several columns. The analyst wants to choose appropriate imputation methods. Which TWO of the following are valid considerations when selecting an imputation technique? (Choose two.)

Accepted Answer

The proportion of missing data in a column affects the reliability of imputation.. The missing data mechanism determines whether imputation can be unbiased, and the proportion of missing data affects reliability. These are key statistical considerations. Mean imputation is not always appropriate, imputation should occur after train-test split to avoid leakage, and efficiency alone is insufficient. Therefore, the mechanism and proportion are the valid considerations.

Answer

Imputation should always use the mean for numerical variables to preserve the distribution.

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Imputation should be performed before splitting data into training and test sets to avoid data leakage.

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The choice of imputation method should be based solely on computational efficiency.

Question 20

A payroll analyst receives a spreadsheet of employee compensation and needs to share aggregate salary statistics with an external benchmarking vendor. Which action best aligns with data minimization principles?

Accepted Answer

Send only the calculated aggregates, such as median and quartile salaries by job family. Data minimization requires that personal data processing and disclosure be limited to what is adequate, relevant, and necessary for the purpose. The benchmarking vendor needs statistics, not records, so computing aggregates by job family removes individual exposure while meeting the business need. Techniques that merely obscure or protect row-level data, such as pseudonyms, encryption, or partial redaction, leave unnecessary personal data in scope.

Answer

Encrypt the spreadsheet with a shared password and email the password in a separate message

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Replace employee names with randomly generated identifiers before sending the file

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Redact Social Security numbers and bank account fields, then send the remaining compensation rows