DA Study Guide 2026
Everything you need to pass the DA exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 DA Exam Format at a Glance
📚 DA Topics to Study (22)
✍️ Sample DA Questions & Answers
1. Which test is appropriate for comparing proportions between two independent groups?
The chi-square test of independence is used to determine if there is a significant association between two categorical variables or proportions.
2. What does the SQL ORDER BY clause do?
ORDER BY sorts query results in ascending (ASC, default) or descending (DESC) order based on specified columns.
3. Which SQL clause limits the number of rows returned by a query?
Different databases use different syntax: LIMIT (MySQL/PostgreSQL), TOP (SQL Server), or ROWNUM (Oracle) to restrict the number of returned rows.
4. What is the primary goal of data mining?
The primary goal of data mining is to extract useful patterns, insights, and knowledge from large datasets. It involves using various techniques to discover hidden relationships and trends that might not be immediately obvious. This knowledge can then be used for decision-making, prediction, and understanding complex systems.
5. What is one-hot encoding used for in data preparation?
One-hot encoding transforms each category level into a separate binary column (0 or 1), enabling algorithms that require numeric input to process categorical data.
6. What is a subquery in SQL?
A subquery is a query embedded within another SQL query, often in the WHERE, FROM, or SELECT clause.