DA0-002 Timed Practice Test 3 — 10 Questions

Question 1

In Tableau, you want to create a view showing the total sales per region, but also want to allow users to filter by year without losing the ability to see all regions. What feature should you use to compute the total sales that ignores the year filter?

10 minute time limit — choose an answer to begin.

Accepted Answer

LOD expression: { FIXED [Region] : SUM([Sales]) }. A Level of Detail (LOD) expression with FIXED can compute a value at the region level, ignoring other dimensions like year.

Answer

Table calculation running total

Answer

Parameter action

Answer

Calculated field using SUM([Sales])

Question 2

A company is merging two databases from different departments. In Database A, customer IDs are integers. In Database B, customer IDs are alphanumeric strings. To merge, the data analyst must reconcile these differences. Which step should be taken first?

Accepted Answer

Perform data profiling to understand the ID formats and relationships. Data profiling is the essential first step before any transformation or mapping. It allows the analyst to examine the actual formats, patterns, and relationships in both ID columns (e.g., whether Database B's alphanumeric IDs contain embedded numeric sequences or consistent prefixes). Without profiling, any conversion or mapping would be based on assumptions that could lead to data loss or incorrect merges.

Answer

Drop the ID column and use a surrogate key

Answer

Convert all IDs to integers using CAST

Answer

Create a mapping table based on the first character

Question 3

A data analyst needs to count the number of orders placed by each customer, but only for customers who have placed more than 5 orders. Which SQL clause should be used to filter the aggregated results?

Accepted Answer

HAVING. HAVING is used to filter groups after aggregation. The query would use GROUP BY customer_id, then HAVING COUNT(*) > 5.

Answer

FILTER

Answer

WHERE

Answer

LIMIT

Question 4

Given the linear regression output, which independent variable has the strongest effect on price, based on standardized coefficients?

Accepted Answer

sqft_living. Standardized coefficients (beta weights) allow comparison of the relative strength of independent variables by measuring the number of standard deviations the dependent variable changes per one standard deviation change in the predictor. In the regression output, sqft_living has the highest absolute standardized coefficient, indicating it has the strongest effect on price. The intercept is not an independent variable and its coefficient is not standardized for comparison.

Answer

bathrooms

Answer

Intercept

Answer

bedrooms

Question 5

Which THREE are best practices for acquiring data via web scraping? (Select exactly 3)

Accepted Answer

Respect robots.txt. Options B, C, and E are correct because best practices for web scraping include respecting robots.txt (ethical and legal compliance), identifying yourself with a user-agent (transparency), and limiting request rate (avoid overloading servers). Option A is incorrect because using multiple IP addresses is often used to circumvent blocking, which can violate terms of service and is not a recommended best practice. Option D is incorrect because scraping all data without regard to terms is unethical and potentially illegal.

Answer

Use multiple IP addresses

Answer

Scrape all data without regard to terms

Question 6

Which TWO of the following are commonly used techniques for handling missing data in a dataset? (Select TWO).

Accepted Answer

Mean imputation. Mean imputation is a commonly used technique for handling missing numerical data where the missing value is replaced with the mean of the observed values for that feature. It preserves the sample size and is simple to implement, though it can reduce variance and distort relationships if data is not missing completely at random.

Answer

Mode imputation

Answer

Dropping columns with missing data

Answer

Dropping rows with missing data

Question 7

A data analyst is extracting data from a relational database using SQL. Which clause is essential for limiting the rows retrieved to only those needed?

Accepted Answer

WHERE. WHERE. The WHERE clause is used to filter rows from a table based on specified conditions, limiting the result set to only the rows that meet those conditions. Option A (GROUP BY) is incorrect because it groups rows with same values into summary rows, not for filtering. Option B (ORDER BY) is incorrect because it sorts the result set, not filters. Option D (HAVING) is incorrect because it filters groups after aggregation, not individual rows. Therefore, WHERE is essential for limiting rows retrieved.

Answer

GROUP BY

Answer

ORDER BY

Answer

HAVING

Question 8

A financial analyst needs to show how net income is derived from revenue, costs, and expenses over a period. The chart should highlight the contribution of each component. Which chart type is most appropriate?

Accepted Answer

Waterfall chart. A waterfall chart shows how an initial value is affected by a series of positive and negative changes, making it ideal for financial breakdowns.

Answer

Line chart

Answer

Area chart

Answer

Pie chart

Question 9

A business analyst needs to explain to a sales director that the reported revenue has a 95% confidence interval of ±2%. Which concept is being communicated?

Accepted Answer

Uncertainty communication. Confidence intervals quantify the uncertainty around a metric, conveying that the true value may vary.

Answer

Data governance

Answer

Single version of truth

Answer

Data lineage

Question 10

A data analyst notices that customer addresses in the database contain invalid ZIP codes. Which data quality dimension is being violated?

Accepted Answer

Validity. A is correct because validity refers to the degree to which data conforms to its defined format, rules, or constraints. Invalid ZIP codes (e.g., a five-digit code containing letters or a non-existent postal code) directly violate the format and domain rules expected for that field, making this a validity issue.

Answer

Timeliness

Answer

Consistency

Answer

Completeness