Prepare and Clean Datasets SNOWPRO-ADVANCED-DATA-ANALYST Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   Which of the following is an example of standardizing a format?

   • AFilling missing values with the median
   • BConverting all date strings to the 'YYYY-MM-DD' format
   • CRemoving duplicate rows from a table
   • DCreating a new column that is the product of two existing columns
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2. 17foundation · easy

   Which type of join returns only the rows that have matching keys in both tables?

   • ARIGHT JOIN
   • BFULL OUTER JOIN
   • CLEFT JOIN
   • DINNER JOIN
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4. 18expert · hard

   An analyst needs to join a 'customers' table (with 'customer_id' as the primary key) to an 'orders' table (with 'customer_id' as a foreign key). The analyst wants to ensure that all customers are included in the result, even if they have no orders. However, the analyst also wants to verify that no customer_id in the orders table is missing from the customers table. What is the best approach?

   • APerform an INNER JOIN and rely on the foreign key constraint to ensure data integrity.
   • BPerform a RIGHT JOIN from customers to orders.
   • CPerform a FULL OUTER JOIN and filter for NULLs in either key.
   • DPerform a LEFT JOIN from customers to orders, then run a separate query to find orders with no matching customer.
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5. 19application · hard

   A healthcare analytics team is preparing a patient outcomes dataset for a regression model. The 'discharge_date' column has 15% NULL values, and the 'readmission_flag' column has 5% NULL values. The model requires complete cases for both features. The team wants to preserve as much information as possible while maintaining data integrity. What should they do?

   • AImpute discharge_date using a model based on admission_date and length_of_stay, and impute readmission_flag using logistic regression on other features.
   • BReplace NULL discharge_date with the admission_date and set readmission_flag to 0.
   • CRemove all rows with NULL in either column, since the model requires complete cases.
   • DImpute discharge_date with the median date and readmission_flag with the mode.
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6. 20foundation · easy

   Which activity is the primary purpose of data profiling?

   • AEnforcing data privacy policies on sensitive columns
   • BTransforming data into a standardized format for storage
   • CAssessing data quality by examining structure, content, and relationships
   • DDeleting duplicate rows from a table
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