Mep Media Junior Data Analyst Interview Questions and Answers

I am a recent graduate with a degree in Data Science and a passion for analyzing and interpreting data to drive business decisions.

• Recent graduate with a degree in Data Science

• Passionate about analyzing and interpreting data

• Strong skills in statistical analysis and data visualization

• Experience with programming languages such as Python and R

• Completed internships in data analysis roles

Power BI is a business analytics tool by Microsoft that provides interactive visualizations and business intelligence capabilities.

• Developed by Microsoft

• Allows users to create interactive visualizations and reports

• Integrates with various data sources such as Excel, SQL databases, and cloud services

• Enables data exploration and sharing insights with stakeholders

• Offers features like dashboards, data connections, and data ...read more

SQL is a programming language used for managing and manipulating relational databases.

• SQL stands for Structured Query Language

• It is used to communicate with databases to perform tasks such as querying data, updating data, and creating tables

• Common SQL commands include SELECT, INSERT, UPDATE, DELETE

• Example: SELECT * FROM table_name WHERE condition;

ETL stands for Extract, Transform, Load. It is a process used to extract data from various sources, transform it into a consistent format, and load it into a data warehouse for analysis.

• Extract: Data is extracted from multiple sources such as databases, files, APIs, etc.

• Transform: Data is cleaned, standardized, and transformed into a consistent format suitable for analysis.

• Load: The transformed data is loaded into a da...read more

Types of keys in data analysis include primary keys, foreign keys, and composite keys.

• Primary key uniquely identifies each record in a table (e.g. customer ID)

• Foreign key links two tables together (e.g. customer ID in orders table)

• Composite key consists of multiple columns to uniquely identify a record (e.g. combination of customer ID and order ID)

Join is a SQL operation used to combine rows from two or more tables based on a related column between them.

• Join is used to retrieve data from multiple tables based on a related column.

• Common types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;

Cross join produces Cartesian product of two tables, while outer join combines rows from two tables based on a related column.

• Cross join returns all possible combinations of rows from two tables.

• Outer join combines rows from two tables based on a related column, including unmatched rows with NULL values.

• Example: Cross join - SELECT * FROM table1 CROSS JOIN table2

• Example: Outer join - SELECT * FROM table1 LEFT JOIN tabl...read more

Facts are measurable data points, while dimensions provide context to the facts by categorizing and organizing them.

• Facts are quantitative data that can be measured or counted.

• Dimensions provide context to the facts by categorizing and organizing them.

• In a sales database, the fact could be the total revenue generated, while dimensions could include product category, region, and time period.

TRUNCATE removes all rows from a table, DELETE removes specific rows, and DROP deletes the entire table structure.

• TRUNCATE is faster than DELETE as it does not log individual row deletions.

• DELETE is slower than TRUNCATE as it logs each row deletion.

• DROP removes the entire table structure along with all data.

• TRUNCATE and DELETE can be rolled back, but DROP cannot be rolled back.

• Example: TRUNCATE table_name;

• Example: DELE...read more

SQL is a programming language used for managing and analyzing data in relational databases.

• SQL stands for Structured Query Language

• It is used to retrieve, manipulate, and analyze data stored in relational databases

• SQL is important in data analytics as it allows analysts to query databases to extract relevant information for analysis

• It helps in filtering, sorting, and aggregating data to generate insights

• Examples of SQL...read more

Different types of SQL joins used to combine rows from two or more tables based on a related column between them.

• INNER JOIN: Returns rows when there is at least one match in both tables.

• LEFT JOIN: Returns all rows from the left table and the matched rows from the right table.

• RIGHT JOIN: Returns all rows from the right table and the matched rows from the left table.

• FULL OUTER JOIN: Returns all rows when there is a match...read more

WHERE clause is used to filter rows before grouping, while HAVING clause is used to filter groups after grouping.

• WHERE clause is used with SELECT, UPDATE, DELETE statements to filter rows based on a condition

• HAVING clause is used with SELECT statement to filter groups based on a condition

• WHERE clause is applied before the data is grouped, while HAVING clause is applied after the data is grouped

• Example: SELECT * FROM ta...read more

Append adds rows to a dataset, while Merge combines datasets based on a common key.

• Append adds rows to the bottom of a dataset, increasing the number of observations.

• Merge combines datasets based on a common key, such as a unique identifier or variable.

• Appending is useful for adding new data, while merging is useful for combining related datasets.

• Example: Appending a new month of sales data to an existing dataset. Merg...read more

Row-level security in Power BI allows restricting access to specific rows of data based on user roles.

• Row-level security in Power BI is used to control access to data at the row level based on user roles.

• Roles in Power BI define the level of access users have to data and reports.

• Examples of roles in Power BI include Admin, Analyst, Viewer, and Contributor.

• By setting up row-level security, users can only see the data th...read more

Bookmarks are digital markers used to quickly navigate to specific sections or pages within a document or website.

• Bookmarks allow users to easily access important or frequently visited sections of a document or website.

• They are commonly used in web browsers to save specific web pages for quick access.

• Bookmarks can also be used in PDF documents to mark important pages or sections for easy reference.

Duplicate refers to an exact copy, while reference is a pointer to the original object.

• Duplicate is a separate copy of the original data, while reference points to the original data.

• Changing a duplicate does not affect the original, but changing a reference does.

• Duplicates consume more memory than references.

• Example: Duplicate - making a photocopy of a document. Reference - sharing a link to a document.

• Example: Duplica...read more

Left Join includes all records from the left table and matching records from the right table. Right Join includes all records from the right table and matching records from the left table. Cross Join combines all records from both tables.

• Left Join: Includes all records from the left table and matching records from the right table.

• Right Join: Includes all records from the right table and matching records from the left t...read more

Indexing is a technique used to optimize data retrieval in databases by creating indexes on columns.

• Types of indexing include clustered and non-clustered indexes

• Clustered indexes physically reorder the data in the table based on the index key

• Non-clustered indexes create a separate structure to store the index key and a pointer to the actual data

• Indexes are used to speed up data retrieval operations such as SELECT queri...read more

Union combines and removes duplicates, Union all combines without removing duplicates.

• Union combines result sets and removes duplicates

• Union all combines result sets without removing duplicates

• Union is slower than Union all as it involves removing duplicates

• Union all is faster than Union as it does not remove duplicates

To find the 3rd highest salary or marks, you can use SQL query with ORDER BY and LIMIT.

• Use SQL query with ORDER BY to sort the salaries or marks in descending order

• Use LIMIT 2,1 to skip the first two highest salaries or marks and get the third highest

PARTITION BY is used to divide the result set into partitions, while ORDER BY is used to sort the rows within each partition in window functions.

• PARTITION BY is used to group rows with the same values in specified columns

• ORDER BY is used to sort the rows within each partition

• Example: SELECT column1, column2, SUM(column3) OVER (PARTITION BY column1 ORDER BY column2) AS total FROM table_name

Window functions like ROW_NUMBER(), RANK(), and DENSE_RANK() assign a unique number to each row based on specified criteria.

• ROW_NUMBER() assigns a unique sequential integer starting from 1 to each row within a partition

• RANK() assigns a unique rank to each row within a partition, with no gaps in ranking if there are ties

• DENSE_RANK() assigns a unique rank to each row within a partition, with possible gaps in ranking if t...read more

I found data cleaning and manipulation to be the most difficult part of my work.

• Understanding and cleaning messy data sets

• Manipulating data to fit the required format

• Dealing with missing or inconsistent data

• Creating new variables or features from existing data

• Ensuring data quality and accuracy

I have a strong analytical background, excellent problem-solving skills, and a passion for data-driven decision making.

• I have a degree in Statistics and experience with data analysis tools such as Python and SQL.

• I have successfully completed projects where I analyzed large datasets to provide actionable insights.

• I am detail-oriented and have a proven track record of delivering accurate and timely results.

In five years, I see myself as a Senior Data Analyst leading a team and working on more complex projects.

• Advancing to a Senior Data Analyst role

• Leading a team of junior analysts

• Working on more complex and challenging projects

• Continuing to learn and grow in the field of data analysis