Top 20 Data Analysts Question and Answer

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11. What is a foreign key in a database?

A unique identifier for a record
A field that links to a primary key in another table
A field that can be left empty
A table used for foreign data

12. What is the purpose of the COUNT function in SQL?

To find the maximum value
To count the number of rows
To return the sum of values
To find the average value

13. What is the role of a data analyst?

Writing machine learning algorithms
Interpreting and analyzing data to help business decisions
Developing software applications
Managing databases

14. What does a VLOOKUP function in Excel do?

It returns the smallest value in a range
It looks for a value in a column and returns a value from a different column
It sorts data by ascending order
It averages values from multiple columns

15. What is a JOIN operation in SQL?

It filters rows by a condition
It combines rows from two or more tables based on a related column
It deletes data from multiple tables
It creates a new table

16. In Python, what is the main purpose of the Matplotlib library?

To create visualizations like graphs and charts
To perform mathematical operations
To manage datasets
To clean missing data

17. What is the purpose of data cleansing?

To transform data into charts
To remove errors and inconsistencies in the data
To backup the data
To analyze the data

18. What is an outlier in a dataset?

A data point that is always included in analysis
A data point that significantly differs from other data points
A data point that is missing
A common value in the dataset

19. Which Python library is commonly used for numerical computing?

Pandas
NumPy
Matplotlib
Seaborn

20. What is data wrangling?

The process of creating data visualizations
The process of transforming and mapping raw data for analysis
The process of collecting data from external sources
The process of sharing data across teams

21. What is linear regression used for?

Predicting the value of a dependent variable based on an independent variable
Classifying data into categories
Clustering data
Summarizing data

22. What does the term "big data" refer to?

A small dataset that is easy to process
Extremely large datasets that require special tools to process
Data stored in Excel
Data used for training machine learning models

23. What is the main function of a pivot table in Excel?

Summarize large datasets by grouping and aggregating data
Create visual graphs and charts
Perform linear regression
Perform database queries

24. What is data governance?

The management of data policies, procedures, and standards
The process of creating data visualizations
The process of cleaning data
The analysis of big data

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25. In Python, which library is primarily used for data visualization?

Pandas
NumPy
Matplotlib
TensorFlow

26. What is the purpose of the HAVING clause in SQL?

To filter records in a database
To join two tables
To filter results after aggregation
To create indexes

27. What does the GROUP BY clause do in SQL?

Groups rows that have the same values into summary rows
Sorts rows in ascending order
Joins tables on a foreign key
Deletes duplicate rows

28. What is the main advantage of using a relational database?

Unstructured data storage
Efficient data retrieval using relationships between tables
Easy storage of images and videos
Limited to small datasets

29. What is the purpose of the DISTINCT keyword in SQL?

To group data by specific values
To remove duplicate rows from the result set
To join multiple tables
To return only the first row

30. What is the median of the dataset {10, 20, 30, 40, 50}?

10
30
40
50