DA0-002 Practice Test 8 — 10 Questions

Question 1

In Power BI, a developer needs to create a measure that calculates total sales for the same period last year. Which DAX function should be used?

Accepted Answer

SAMEPERIODLASTYEAR. SAMEPERIODLASTYEAR is a DAX time intelligence function that returns a table of dates shifted back exactly one year, ideal for year-over-year comparisons. It is specifically designed for calculating metrics like total sales for the same period last year when used with a date table. This function is simple and directly addresses the requirement.

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TOTALYTD

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PARALLELPERIOD

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DATEADD

Question 2

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 enforces referential integrity by requiring that values in a column match values in the primary key (or unique key) column of another table. This is exactly the rule described — ensuring every value in one table's column corresponds to a primary key value in another table.

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Unique constraint

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Primary key

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Check constraint

Question 3

A company’s marketing team wants to segment customers based on purchase history, demographics, and website behavior. The data includes both numeric and categorical variables. Which clustering algorithm is best suited for handling mixed data types?

Accepted Answer

Hierarchical clustering with Gower distance. Hierarchical clustering with Gower distance is best suited for mixed data types because Gower distance computes a dissimilarity measure that handles both numeric and categorical variables by normalizing numeric differences and using a simple matching coefficient for categorical ones. This allows the algorithm to create a distance matrix that equally weights all variable types, making it ideal for segmenting customers with purchase history, demographics, and website behavior data.

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K-modes clustering

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DBSCAN with Euclidean distance

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K-means clustering

Question 4

An analyst computed the mean, median, and mode of a dataset and found they are all equal. Which of the following best describes the distribution?

Accepted Answer

Symmetric. When mean, median, and mode are equal, the distribution is symmetric and unimodal, often resembling a normal distribution.

Answer

Bimodal

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Negatively skewed

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Positively skewed

Question 5

A data analyst is working with a dataset containing house prices. After building a multiple linear regression model, the analyst observes that the model performs well on training data but poorly on validation data. Which technique is most appropriate to address this issue?

Accepted Answer

Apply L2 regularization (Ridge). The model is overfitting the training data, as evidenced by high performance on training data but poor performance on validation data. L2 regularization (Ridge) adds a penalty term proportional to the square of the coefficients, which shrinks them and reduces model complexity, thereby improving generalization to unseen data.

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Decrease the training data size

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Use a polynomial transformation

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Increase the number of features

Question 6

A data team must implement a data retention policy to reduce storage costs while meeting legal requirements. Which TWO actions best achieve this?

Accepted Answer

Set data retention limits with automated deletion. Option A is correct because setting data retention limits with automated deletion enforces the legal retention policy by removing data once its required retention period expires, directly reducing stored volume and storage costs. Option E is correct because archiving historical data to tape or cloud archive tiers moves infrequently accessed data to much cheaper storage media while still preserving it for legal and compliance requirements. Together, these two actions address both cost reduction and legal retention. Option B (data compression) reduces the size of stored data but does not enforce retention or remove data that has exceeded its legal retention period. Option C (increasing primary storage capacity) raises costs rather than reducing them and does nothing to meet retention requirements. Option D (data deduplication) eliminates redundant copies but does not implement a retention policy or remove expired data.

Answer

Use data compression

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Increase primary storage capacity

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Implement data deduplication

Question 7

A university database stores student information in a normalized schema. The 'students' table has a primary key 'student_id'. The 'enrollments' table has a foreign key 'student_id' referencing 'students'. Which two of the following are true about primary and foreign keys? (Select TWO)

Accepted Answer

A foreign key ensures referential integrity between tables. A foreign key enforces referential integrity by ensuring that every value in the foreign key column of the 'enrollments' table matches a valid primary key value in the 'students' table. This prevents orphaned records and maintains consistency across related tables in a normalized relational database.

Answer

A foreign key must have the same name as the primary key it references

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A foreign key can reference a column that is not a primary key

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A table can have multiple primary keys

Question 8

A data analyst calculates the mean, median, and mode of a dataset. Which of the following best describes how these measures are used in descriptive statistics?

Accepted Answer

To describe the central tendency of the data. Mean, median, and mode are measures of central tendency, which are used in descriptive statistics to summarize the center point of a dataset. They describe where the data tends to cluster. The correct answer is C because these measures describe the central tendency.

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To identify outliers using standard deviation

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To test hypotheses about population parameters

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To determine the probability of an event

Question 9

A data analyst wants to show the proportion of total sales for each product category. There are 4 categories. Which chart type is most appropriate?

Accepted Answer

Pie chart. A pie chart is designed to show parts of a whole, making it the most appropriate choice for displaying the proportion of total sales contributed by each of four product categories. With only four categories, the slices remain readable and the proportional relationship is immediately clear. Pie charts work best when the number of categories is small (typically 5 or fewer) and the values sum to a meaningful total.

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Line chart

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Scatter plot

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Histogram

Question 10

An analyst creates a histogram of customer transaction amounts but observes that the distribution looks bimodal. Upon review, the analyst realizes that two different customer segments (retail and wholesale) were combined. Which action best addresses this?

Accepted Answer

Create two separate histograms, one for each segment. Creating two separate histograms, one for each customer segment (retail and wholesale), best addresses the bimodal distribution because it allows the analyst to see the underlying distributions of each segment clearly. Combining them into one histogram obscures the distinct patterns, while separating them reveals the true characteristics of each group. This is a fundamental principle of data visualization: when data contains subgroups, disaggregating can provide more meaningful insights.

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Use a single histogram with two colors for segments

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Use a box plot instead of a histogram

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Increase the number of bins to see more detail