| 1. What is data analytics? |
| Answer: Data analytics is the process of examining, cleaning, transforming, and modeling data to extract useful information, draw conclusions, and support decision-making. |
| 2. What are the types of data analytics? |
| Answer: Descriptive, diagnostic, predictive, and prescriptive analysis. |
| 3. Explain the difference between qualitative and quantitative data .? |
| Answer: Qualitative data is non numerical, such as text or images, while quantitative data is numerical, such as measurements or counts. |
| 4. What is data cleansing? |
| Answer: Data cleansing is the process of identifying and correcting errors, inconsistencies, and inaccuracies in asets. |
| 5. What is data outlier? |
| Answer: An outlier is a data point that significantly differs from the rest of the data points in a dataset. |
| 6. Explain the difference between SQL and NOSQL databases? |
| Answer: SQL databases are relational, use structured query language, and have a predefined schema, while NoSQL databases are non-relational, use various query languages, and have a dynamic schema. |
| 7. What is ETL? |
| Answer: ETL stands for Extract, Transform, and Load. It’s a process for retrieving data from various sources, transforming it into a usable format, and loading it into a database or data warehouse. |
| 8. What is primary key in a database? |
| Answer: A primary key is a unique identifier for each record in table. |
| 9. What is foreign key in a database? |
| Answer: A foreign key is a field in a table that refers to the primary key of another table, establishing a relationship between the two tables. |
| 10. Explain the difference between inner join and outer join in SQL ? |
| Answer: Inner join returns records with matching values in both tables, while outer join returns records from one table and the matching records from the other table, filing in NULL values for non-matching records. |
| 11. What is a histogram? |
| Answer: A histogram is a graphical representation of the distribution of a dataset, showing the frequency of data points in specified intervals. |
| 12. What is a box plot? |
| Answer: A box plot is a graphical representation of the distribution of a dataset, showing the median, quartiles and possible outliers. |
| 13. What is linear regression? |
| Answer: Linear regression is a statistical method used to mode the relationship between a dependent variable and one or more independent variables. |
| 14. What is overfitting? |
| Answer: Overfitting occurs when a model is too complex and performs well. |
| 15. Explain the difference between R- squared and adjusted R-squared? |
| Answer: R-squared measures the proportion of variation in the dependent variable explained by the independent variables, while adjusted R-squared adjusts for the number of independent variables in the model. |
| 16. What is a confusion matrix? |
| Answer: A confusion matrix is a table used to evaluate the performance of a classification model, showing the true positives, true negatives, false positives, and false negatives. |
| 17. What is K-means clustering? |
| Answer: K-means clustering is an unsupervised machine learning algorithm used to partition data into k clusters based on their similarity. |
| 18. What is cross-validation? |
| Answer: Cross-validation is a technique used to evaluate the performance of a model by splitting the dataset into training and testing sets multiple times and calculating the average performance. |
| 19. What is a decision tree? |
| Answer: A decision tree is a flowchart-like structure used in decision making and machine learning, where each internal node represents a feature, each branch represents a decision rule, and each leaf node represents an outcome. |
| 20. What is the difference between supervised and unsupervised learning? |
| Answer: Supervised learning uses labeled data and a known output, while unsupervised learning uses unlabeled data and discovers patterns or structures in the data. |
| 21. Explain principal component analysis (PCA)? |
| Answer: PCA is a dimensionality reduction technique that transforms data into a new coordinate system, reducing the number of dimensions while retaining as much information as possible. |
| 22. What is time series analysis? |
| Answer: Time series analysis is a statistical technique for analyzing and forecasting data points collected over time, such as stock prices or weather data. |
| 23. What is difference between a bar chart and a pie chart? |
| Answer: A bar chart represents data using rectangular bars, showing the relationship between categories and values, while a pie chart represents data as slices of a circle, showing the relative proportion of each category. |
| 24. What is a pivot table? |
| Answer: A pivot table is a data summarization tool that allows users to reorganize, filter, and aggregate data in a spreadsheet or database. |
| 25. What is data normalization? |
| Answer: Data normalization is the process of scaling and transforming data to eliminate redundancy and improve consistency, making it easier to compare and analyze. |
| 26. Explain the concept of data warehousing? |
| Answer: A data warehouse is a large, centralized repository of data used for reporting and analysis, combining data from different sources and organizing it for efficient querying and reporting. |
| 27. What is the role of a data analyst in a company? |
| Answer: A data analyst collects, processes, and analyzes data to help organizations make informed decisions, identify trends, and improve efficiency. |
| 28. How do you handle missing data in a dataset? |
| Answer: Missing data can be handled by imputing values (mean, median, mode), deleting rows with missing data, or using models that can handle missing data. |
| 29. How do you deal with outliers in a dataset? |
| Answer: Outliers can be dealt with by deleting, transforming, or replacing them, or by using models that are less sensitive to outliers. |
| 30. Describe a situation where you used data analysis to solve a problem? |
| Answer: Answer this based on your personal experience, detailing the problem, your approach, and the outcome. |
| 31. How do you ensure data quality and accuracy in your analysis? |
| Answer: Ensuring data quality and accuracy involves data cleansing, validation, normalization, and cross-referencing with other sources, as we I as using appropriate analytical methods and tools. |
| 32. How do you handle large datasets? |
| Answer: Handling large datasets involves using efficient data storage and processing techniques, such as SQL databases, parallel computing, or cloud-based solutions, and optimizing code and algorithms for performance. |
| 33. What is your experience with data visualization tools, such as Tableau, Power Bl, or Excel ? |
| Answer: Answer this based on your personal experience and familiarity with the mentioned tools, providing examples of projects or tasks you have completed using them |
| 34. How do you stay. updated on the latest trends and developments in data analysis ? |
| Answer: Mention resources such as blogs, podcasts, online courses, conferences, and industry publications that you use to stay informed and up-to-date. |
| 35. How do you handle data privacy and security concerns in your analysis? |
| Answer: By following data protection regulations, anonymizing sensitive data, using secure data storage and transfer methods, and implementing access controls and encryption when necessary. |
| 36. How do you prioritize tasks when working on multiple data analysis projects? |
| Answer: By setting clear goals, assessing deadlines and project importance, allocating resources efficiently, and using project management tools or techniques to stay organized |
| 37. How do you handle disagreements or conflicts with in a team? |
| Answer: By openly discussing the issue, actively listening to different perspectives, finding common ground, and working collaboratively to reach a resolution. |
| 38. Describe a situation where you had to present complex data analysis results to a non-technical audience ? |
| Answer: Answer this based on your personal experience, detailing how you simplified the information, used visual aids, and adapted your communication style for the audience. |
| 39. How do you ensure your data analysis is unbiased ? |
| Answer: By being aware of potential biases, using diverse data sources, applying objective analytical methods, and cross-validating results with other sources or techniques. |
| 40. How do you validate the results of your data analysis? |
| Answer: By using cross-validation, holdout samples, comparing results with known benchmarks, and checking for consistency and reasonableness in the findings. |