30+ Associate Data Analyst Interview Questions and Answers

Stored procedures are pre-written SQL codes that can be saved and reused. They are used to improve performance and security.

• Stored procedures are used to reduce network traffic by executing a batch of SQL statements at once.

• They can improve performance by reducing the amount of time spent parsing and optimizing SQL statements.

• Stored procedures can also enhance security by allowing access to only specific parts of the database.

• Examples of stored procedures include creating a n...read more

The finding from the project was that there is a strong correlation between customer satisfaction and repeat purchases.

• The project analyzed customer satisfaction surveys and purchase data

• The data showed that customers who reported high satisfaction scores were more likely to make repeat purchases

• This finding suggests that improving customer satisfaction can lead to increased customer loyalty and revenue

Three things I learned from my Data Science and Analytics course are statistical analysis, data visualization, and machine learning.

• Statistical analysis: Learned how to use statistical methods to analyze data and draw conclusions.

• Data visualization: Learned how to create visual representations of data to better understand patterns and trends.

• Machine learning: Learned how to use algorithms to build predictive models and make data-driven decisions.

SQL query to get the second row from the top.

• Use the LIMIT keyword to limit the number of rows returned.

• Use the OFFSET keyword to skip the first row.

• Order the rows by a column to ensure consistent results.

To get non-repeated entries from a table, use the DISTINCT keyword in SQL.

• Use SELECT DISTINCT column_name FROM table_name

• DISTINCT keyword returns only unique values

• Can be used with multiple columns

• Can also use GROUP BY clause

I have experience with various machine learning models such as linear regression, decision trees, random forests, and neural networks.

• Linear regression is used for predicting continuous outcomes.

• Decision trees are used for classification and regression tasks.

• Random forests are an ensemble method that combines multiple decision trees for improved accuracy.

• Neural networks are used for complex pattern recognition and prediction tasks.

vlookup is a function in Excel used to search for a specific value in a table and return a corresponding value from another column.

• vlookup stands for 'vertical lookup'

• It requires a lookup value, a table array, column index number, and an optional range lookup value

• It can only search for values in the leftmost column of the table array

• It returns the first matching value found, so it may not be accurate if there are duplicates

• It can be slow and inefficient for large datasets

Multi-threading and multi-tasking are techniques used to improve the performance of a computer system.

• Multi-threading is the ability of a CPU to run multiple threads of execution concurrently.

• Multi-tasking is the ability of an operating system to run multiple applications or processes concurrently.

• Multi-threading is used to improve the performance of a single application by dividing it into smaller threads that can run concurrently.

• Multi-tasking is used to improve the overall...read more

Primary key uniquely identifies a record in a table, while a unique key ensures that all values in a column are distinct.

• Primary key is a column or set of columns that uniquely identifies each row in a table

• Primary key cannot have null values

• A table can have only one primary key

• Unique key is a column or set of columns that ensures that all values in the column(s) are distinct

• Unique key can have null values, but only one null value is allowed

• A table can have multiple unique ke...read more

Query to find rows beginning with a letter in SQL

• Use the LIKE operator with the pattern '[letter]%'

• Replace [letter] with the desired letter

• Enclose the pattern in single quotes

• Example: SELECT * FROM table_name WHERE column_name LIKE 'A%'

Use a line chart to show year-wise trend.

• Line chart is the best option to show year-wise trend.

• It helps to visualize the trend over time.

• X-axis represents the year and Y-axis represents the data points.

• Multiple lines can be used to compare trends.

• Example: Line chart showing the sales trend of a company from 2015 to 2020.

I analyze data from multiple sources by integrating, cleaning, and visualizing data to derive insights and support decision-making.

• Identify relevant data sources such as databases, APIs, and spreadsheets.

• Use ETL (Extract, Transform, Load) processes to consolidate data.

• Example: Combining sales data from a CRM with marketing data from social media.

• Perform data cleaning to handle missing values and inconsistencies.

• Utilize tools like SQL for querying and Python or R for analysis....read more

Oops features are object-oriented programming concepts that help in creating reusable and modular code.

• Encapsulation - bundling data and methods that operate on that data within a single unit

• Inheritance - creating new classes from existing ones, inheriting their properties and methods

• Polymorphism - ability of objects to take on multiple forms or behaviors

• Abstraction - hiding implementation details and showing only the necessary information

A primary key is a unique identifier for a record in a database table.

• Primary key ensures that each record in a table is unique

• It is used to establish relationships between tables

• It cannot contain null values

• Examples include social security numbers, email addresses, and employee IDs

Bar chart is used to compare different categories, while histogram is used to show distribution of continuous data.

• Bar chart has discrete categories on x-axis, while histogram has continuous data on x-axis.

• Bar chart has gaps between bars, while histogram bars are adjacent to each other.

• Bar chart is used for categorical data, while histogram is used for numerical data.

• Example: Bar chart can show sales data for different products, while histogram can show distribution of height...read more

To find duplicates in Excel, use the conditional formatting feature or the Remove Duplicates tool.

• Select the range of cells where you want to find duplicates

• Go to the 'Home' tab and click on 'Conditional Formatting'

• Select 'Highlight Cells Rules' and then 'Duplicate Values'

• Choose the formatting style and click 'OK'

• Alternatively, go to the 'Data' tab and click on 'Remove Duplicates'

• Select the columns where you want to find duplicates and click 'OK'

Object oriented programming language is a programming paradigm that uses objects to represent data and methods to manipulate that data.

• Object oriented programming languages include Java, Python, C++, Ruby, and many others.

• Objects are instances of classes, which define the properties and behaviors of the object.

• Encapsulation, inheritance, and polymorphism are key concepts in object oriented programming.

• Example: In Java, a class can be defined to represent a car, with propertie...read more

I have worked on Tableau, Power BI, and Excel for data visualization.

• Tableau for creating interactive dashboards and visualizations

• Power BI for creating reports and visualizations with real-time data

• Excel for creating basic charts and graphs

Minimum number of chess boards required for a tournament puzzle.

• Each game requires one board

• In each round, half of the players will be eliminated

• The number of players in the first round will determine the number of boards needed

• The formula to calculate the number of boards needed is: ceil(total number of players / 2)

A pivot table is a data summarization tool used in spreadsheet programs to analyze, summarize, and present data.

• Allows users to reorganize and summarize selected columns and rows of data

• Helps in analyzing trends, patterns, and relationships within the data

• Enables users to perform calculations, such as sums, averages, counts, etc., on the summarized data

• Provides a dynamic way to view and manipulate data for better decision-making

• Commonly used in Excel, Google Sheets, and other...read more

Joining two tables in SQL involves using the JOIN keyword and specifying the columns to join on.

• Use the JOIN keyword followed by the name of the second table

• Specify the columns to join on using the ON keyword

• There are different types of joins such as INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN

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

Query to find duplicates in SQL

• Use GROUP BY clause to group the columns that may have duplicates

• Use HAVING clause to filter the groups that have more than one row

• Use COUNT() function to count the number of rows in each group

Left Join is a type of join operation in SQL that returns all rows from the left table and the matched rows from the right table.

• Left Join combines rows from two tables based on a related column between them.

• It includes all rows from the left table, even if there are no matches in the right table.

• If there are no matches, NULL values are included for columns from the right table.

• Example: SELECT * FROM table1 LEFT JOIN table2 ON table1.id = table2.id;

The 25 Horse Problem is a logic puzzle that involves determining the fastest 3 horses out of 25 using minimal races.

• Divide the 25 horses into groups of 5 and race them to determine the fastest horse in each group.

• Then race the fastest horses from each group to determine the top 3 fastest horses overall.

• This approach minimizes the number of races needed to find the top 3 horses.

A virtual function is a function in a base class that is declared using the keyword 'virtual' and can be overridden by a function with the same signature in a derived class.

• Virtual functions allow for dynamic polymorphism in object-oriented programming.

• They are used to achieve runtime polymorphism by allowing a function to be overridden in a derived class.

• Virtual functions are declared in the base class with the 'virtual' keyword and can be overridden in derived classes using...read more

Excel is a powerful spreadsheet program used for data analysis, calculations, and visualization.

• Excel is part of Microsoft Office suite

• It allows users to organize data, perform calculations, and create charts

• Functions like VLOOKUP, SUMIF, and PivotTables are commonly used for data analysis

• Excel can handle large datasets and automate repetitive tasks with macros

Constructor is a special method that is called when an object is created. DBMS stands for Database Management System.

• Constructor is used to initialize the object's state

• DBMS is a software system that manages and organizes data in a database

• Examples of DBMS include MySQL, Oracle, and Microsoft SQL Server