📊 Data Analytics Interview Questions With Answers – Part 2 👇

1️⃣ What is the difference between OLAP and OLTP?
- OLAP (Online Analytical Processing): Used for analysis, complex queries, historical data.
- OLTP (Online Transaction Processing): Used for day-to-day transactions like insert/update/delete.

2️⃣ What are outliers and how do you handle them?
Outliers are data points significantly different from others. Handle using:
- Removal
- Capping
- Transformation (e.g., log scale)
- Using robust models (e.g., decision trees)

3️⃣ What is data normalization?
Normalization scales data to bring all variables to a common range (like 0 to 1). Helps improve model performance.

4️⃣ What is the difference between inner join and outer join?
- Inner Join: Returns only matching rows from both tables.
- Outer Join: Returns all rows from one or both tables, filling with NULLs when no match.

5️⃣ Explain time series analysis.
A method to analyze data points collected or recorded at specific time intervals (e.g., stock prices, sales).

6️⃣ What is hypothesis testing?
A statistical method to test an assumption about a population parameter using sample data.

7️⃣ What are some key challenges in data analytics?
- Data quality & cleanliness
- Handling large volumes
- Data integration from multiple sources
- Choosing the right model/technique

8️⃣ What is A/B Testing?
A/B testing compares two versions of a variable to determine which one performs better (used in product experiments).

9️⃣ What’s the role of a dashboard?
Dashboards visualize KPIs and metrics in real-time for business monitoring and quick decisions.

🔟 How do you ensure data privacy and security?
By using encryption, access controls, anonymization, and following compliance standards like GDPR.

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