Data Analyst
1000+ Data Analyst Interview Questions and Answers
Q1. Suppose there is a room in the office and X people enter room throughout the day, Y people leave throughout the day [continuously people are entering the room, some are staying there, and rest are going out] .....
read moreCode to calculate number of people in a room at EOD given X enter and Y leave throughout the day.
Create a variable to keep track of the current number of people in the room
Increment the variable by X every time someone enters the room
Decrement the variable by Y every time someone leaves the room
Return the final value of the variable at the end of the day
Example: If 10 people enter and 5 leave, there will be 5 people in the room at EOD
Given an array/list of integer numbers 'CHOCOLATES' of size 'N', where each value of the array/list represents the number of chocolates in the packet. There are ‘M’ number of students and the t...read more
Data Analyst Interview Questions and Answers for Freshers
Ninja has been given a string 'STR' containing only lowercase alphabetic characters. Ninja has to find the number of all the different possible substrings of size two that appear in 'STR' as...read more
Given an array/list of integers of length ‘N’, there is a sliding window of size ‘K’ which moves from the beginning of the array, to the very end. You can only see the ‘K’ nu...read more
You are given a string 'STR' of lowercase English alphabets. You need to find the repeated character present first in the string.
Example:
If the string is: “abccba”, then the first repe...read more
Ninja has recently joined the FBI. Ninja got some secret information ‘SECRET_INFORMATION’ which he wants to share with his team. But he can not send this information directly bec...read more
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You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.
Note:
Each pair shou...read more
Ninja is feeling very bored and wants to try something new. So, he decides to find the reverse of a given number. But he cannot do it on his own and needs your help.
Note:
If a number has traili...read more
Data Analyst Jobs
You have been given an array/list 'ARR' of integers. Your task is to find the second largest element present in the 'ARR'.
Note:
a) Duplicate elements may be present. b) If no...read more
You are given an array Arr consisting of N integers. You need to find the equilibrium index of the array.
An index is considered as an equilibrium index if the sum of elements of the array to t...read more
You have been given a binary tree of 'N' unique nodes and a Start node from where the tree will start to burn. Given that the Start node will always exist in the tree, your task is to print the...read more
You are given an infinite supply of coins of each of denominations D = {D0, D1, D2, D3, ...... Dn-1}. You need to figure out the total number of ways W, in which you can make a change fo...read more
You are given a matrix ‘MAT’. Print the transpose of the matrix. The transpose of a matrix is obtained by changing rows to columns and columns to rows. In other words, transpose of a matrix...read more
Given an array/list 'ARR' of ‘N’ distinct integers, you are supposed to find the third largest element in the given array 'ARR'.
Input Format :
The first line contains a single integer ‘T’...read more
Nth term of Fibonacci series F(n), where F(n) is a function, is calculated using the following formula -
F(n) = F(n-1) + F(n-2), Where, F(1) = F(2) = 1
Provided N you have to find out the ...read more
Q16. How can you prove to the client that a students with higher classes are taller than that of lower classes?
We can use statistical analysis to prove that students in higher classes are taller than those in lower classes.
Collect height data of students from different classes
Use statistical measures like mean, median, and mode to compare the heights of students in different classes
Perform hypothesis testing to determine if the difference in height between classes is statistically significant
Visualize the data using graphs and charts to make it easier for the client to understand
Provi...read more
Q17. How to find the minimum number from a given set of numbers ?
To find the minimum number from a set of numbers, compare each number with the others and select the smallest.
Compare each number with the others in the set
Select the smallest number as the minimum
Q18. What are the financial statements? How cost sheet of bank different from cost sheet of manufacturing company? What is debt to equity ratio? What is stock option? What is Stock split? What is lease financing? Na...
read moreFinancial statements, cost sheet, debt to equity ratio, stock option, stock split, lease financing, profitability ratios.
Financial statements are reports that show the financial performance of a company.
Cost sheet of a bank includes interest expenses and income, while cost sheet of a manufacturing company includes direct and indirect costs.
Debt to equity ratio is a financial ratio that shows the proportion of debt and equity used to finance a company's assets.
Stock option is ...read more
Q19. What are the different approach you use for data cleaning.
Different approaches for data cleaning include removing duplicates, handling missing values, correcting inconsistent data, and standardizing formats.
Remove duplicates
Handle missing values
Correct inconsistent data
Standardize formats
Use statistical methods to identify outliers
Check for data accuracy and completeness
Normalize data
Transform data types
Apply data validation rules
Q20. How to Work with dynamic data, how to remove duplicate data or fix the data
To work with dynamic data, remove duplicates and fix errors, use data cleaning techniques.
Use software tools like OpenRefine or Excel to clean data
Identify and remove duplicate data using unique identifiers
Fix errors by standardizing data formats and using regular expressions
Use data validation to ensure accuracy and completeness
Create a data cleaning plan and document all changes made
Test the cleaned data to ensure it meets the desired quality standards
How many Pizza's are sold in one day in Pune?
I was asked a guesstimate how much petrol is used in one day in your city.
Q23. What are the elements which are present in all the financial statements like BS,IS and CF.
The financial statements (BS, IS, CF) have common elements such as assets, liabilities, equity, revenue, expenses, and cash flows.
Assets: resources owned by the company
Liabilities: obligations owed by the company
Equity: residual interest in the assets of the company
Revenue: income generated by the company
Expenses: costs incurred by the company
Cash flows: inflows and outflows of cash
How would you cut a cylindrical cake in 8 equal pieces with just 3 straight cuts of a knife
Q25. 1. Bais and variance trade-off 2. How to handle Imbalanced data? 3. What is Multicollinearity and how do you handle it? 4. Explain Lasso & Ridge? 5. Difference between Bagging and Boosting. 6. Explain K-Means c...
read moreQuestions related to data analysis techniques and methods.
Bais and variance trade-off: balancing model complexity and accuracy
Handling imbalanced data: resampling techniques, adjusting class weights, using different evaluation metrics
Multicollinearity: when predictor variables are highly correlated, can be handled by feature selection or regularization
Lasso & Ridge: regularization techniques to prevent overfitting by adding penalty terms to the loss function
Bagging vs Boostin...read more
Q26. How you get your data in your organization
Data is collected from various sources including databases, APIs, and user input.
We have access to multiple databases where we can extract relevant data
We use APIs to gather data from external sources such as social media platforms
Users can input data through forms or surveys
We also collect data through web scraping techniques
Q27. Sequence of Execution of SQL codes. Select - Where-from-Having- order by etc
The sequence of execution of SQL codes is Select-From-Where-Group By-Having-Order By.
Select: choose the columns to display
From: specify the table(s) to retrieve data from
Where: filter the data based on conditions
Group By: group the data based on a column
Having: filter the grouped data based on conditions
Order By: sort the data based on a column
Q28. What is a Brownian motion? Properties of Brownian motion?
Brownian motion is the random motion of particles in a fluid due to collisions with other particles.
Brownian motion was first observed by Robert Brown in 1827.
It is named after the botanist Robert Brown.
The motion is caused by the random movement of fluid molecules.
Brownian motion is a continuous-time stochastic process.
It is often used to model various phenomena in physics, finance, and biology.
Properties of Brownian motion include random walk, Gaussian distribution, and sel...read more
Q29. Write code to describe database and Columns from a particular table
Code to describe database and columns from a table
Use SQL SELECT statement to retrieve column names and data types
Use DESC command to get table structure
Use INFORMATION_SCHEMA.COLUMNS to get detailed information about columns
Use SHOW CREATE TABLE to get table creation statement
10 coins given and one of the coin is having greater weight then others and we have a measuring device how much least comparison required for finding out the heavy coin
Q31. What is a Martingale? What are Markov Processes? Is Martingale a Markov Process? Are Markov Processes Martingales?
A Martingale is a mathematical concept used in probability theory and statistics. Markov Processes are stochastic processes that satisfy the Markov property.
A Martingale is a sequence of random variables where the expected value of the next variable, given the current and past variables, is equal to the current variable.
Markov Processes are stochastic processes where the future state depends only on the current state and not on the past states.
A Martingale is not necessarily ...read more
Q32. 1) What Is IPO 2) Sides Of Balance Sheet 3) What Is Depreciation 4) Financial Statements
Questions related to finance and accounting
IPO stands for Initial Public Offering, which is the first time a company's stock is offered to the public
Balance sheet has two sides - assets and liabilities & equity
Depreciation is the decrease in value of an asset over time due to wear and tear or obsolescence
Financial statements include income statement, balance sheet, and cash flow statement
Q33. Write a query where all the customer name start with A
Query to retrieve all customer names starting with A.
Use the SELECT statement to retrieve customer names.
Use the LIKE operator with the pattern 'A%' to match names starting with A.
Specify the table and column name where the customer names are stored.
Example: SELECT customer_name FROM customers WHERE customer_name LIKE 'A%';
Q34. Define Excel Functions Sum , Sum if , Count , CountA , Count Blanks
Excel functions are pre-built formulas that perform calculations or manipulate data in a spreadsheet.
Sum: adds up a range of numbers
Sum if: adds up a range of numbers based on a specified condition
Count: counts the number of cells in a range that contain numbers
CountA: counts the number of cells in a range that are not empty
Count Blanks: counts the number of empty cells in a range
Q35. Difference between Having and where clause?
HAVING clause is used with GROUP BY to filter the results based on aggregate functions, while WHERE clause is used to filter individual rows.
HAVING clause is used after GROUP BY clause.
HAVING clause is used to filter the results based on aggregate functions like SUM, COUNT, AVG, etc.
WHERE clause is used before GROUP BY clause.
WHERE clause is used to filter individual rows based on conditions.
HAVING clause cannot be used without GROUP BY clause.
WHERE clause can be used without...read more
Q36. What is SQL, what are the types of joins and what is the main difference between union and union all ?
SQL is a programming language used for managing relational databases. Joins combine data from multiple tables. Union combines results from multiple queries without duplicates, while Union All includes duplicates.
SQL is a programming language used for managing relational databases.
Types of joins include inner join, left join, right join, and full outer join.
Union combines results from multiple queries without duplicates.
Union All includes duplicates in the combined result set.
Q37. Different types of Joins in SQL and what are the outputs when you join two tables with nulls.
Different types of Joins in SQL and the outputs when joining two tables with nulls.
Types of joins in SQL include inner join, left join, right join, and full outer join.
When joining two tables with nulls, the output depends on the type of join used.
In an inner join, null values are excluded from the result.
In a left join, all rows from the left table and matching rows from the right table are included, with nulls for non-matching rows.
In a right join, all rows from the right t...read more
Q38. How we fill some information in all the selected blank space in just one click in Google sheet ?
Yes, we can use the Fill Down feature in Google Sheets to fill information in all selected blank spaces in just one click.
Select the cell with the information you want to fill
Hover over the bottom right corner of the cell until the cursor changes to a small blue square
Click and drag the blue square down to the last cell where you want the information to be filled
I was asked how to manage warehouse of a brand having Stores in various cities during high demand and low supply during times like covid.
Q40. What is the effect of stock split on market capitalisation of a company?
A stock split increases the number of shares outstanding and decreases the price per share, but does not affect the market capitalisation.
Stock split does not affect the total value of the company
Market capitalisation remains the same after a stock split
Stock split increases the number of shares outstanding and decreases the price per share
For example, if a company has 1 million shares outstanding and the stock splits 2-for-1, the company will have 2 million shares outstandin...read more
Q41. Can we add extra row and pivot table in excel? If yes than how?
Yes, we can add extra row and pivot table in excel.
To add a row, select the row below where you want to add the new row and right-click, then select 'Insert'.
To create a pivot table, select the data range and go to 'Insert' tab, click on 'PivotTable' and follow the prompts.
To add a new pivot table to an existing one, select a cell in the existing pivot table and go to 'Analyze' tab, click on 'PivotTable' and follow the prompts.
Q42. Create the pivot table, sort the data in ascending order
Create a pivot table and sort the data in ascending order.
To create a pivot table, select the data range and go to the 'Insert' tab in Excel.
Choose 'PivotTable' and select the location for the pivot table.
Drag the desired fields to the 'Rows' and 'Values' areas.
To sort the data in ascending order, click on the drop-down arrow next to the field name in the pivot table and select 'Sort A to Z'.
Q43. What is aadhar card (because i am in aadhhar process)
Aadhaar card is a unique identification card issued by the Indian government to residents of India.
Aadhaar card is a 12-digit unique identification number issued by the Unique Identification Authority of India (UIDAI).
It serves as proof of identity and address for Indian residents.
Aadhaar card contains biometric and demographic information of the cardholder, including fingerprints and iris scans.
It is used for various purposes such as opening bank accounts, getting a SIM card...read more
Q44. What is permutation and combination and how is it used in data science?
Permutation and combination are mathematical concepts used to count the number of possible outcomes in a given scenario.
Permutation is the arrangement of objects in a specific order while combination is the selection of objects without considering the order.
Permutation formula: nPr = n!/(n-r)! where n is the total number of objects and r is the number of objects selected.
Combination formula: nCr = n!/r!(n-r)! where n is the total number of objects and r is the number of objec...read more
Q45. Given a list of dictionary, find the dictionary which has the count of key highest among all the dictionaries. eg: [{a:5},{b:2}.......] Now here 5 is the highest key value so it should be printed.
Find the dictionary with the highest count of keys in a list of dictionaries.
Iterate through the list of dictionaries and keep track of the dictionary with the highest count of keys.
Use a loop to count the keys in each dictionary and compare it with the current highest count.
Return the dictionary with the highest count of keys.
Q46. Difference between CSV file and Excel file
CSV files are plain text files that store tabular data, while Excel files are binary files that can contain multiple sheets and complex formatting.
CSV files are simpler and more lightweight compared to Excel files.
CSV files can be easily opened and edited using a text editor, while Excel files require specific software like Microsoft Excel.
CSV files do not support formulas, macros, or formatting options like colors and fonts, while Excel files do.
CSV files have a smaller file...read more
Q47. Explain reconciliation assignment that you have done in first step.
Reconciliation assignment involves comparing and matching data from different sources.
Identify sources of data to be reconciled
Compare data from different sources
Match data based on common identifiers
Resolve discrepancies and errors
Ensure accuracy and completeness of reconciled data
Q48. How much amount of data you Handel till now.
I have handled large amounts of data in my previous roles.
I have experience handling terabytes of data in my previous role as a data analyst at XYZ company.
I have worked with data from various sources such as databases, spreadsheets, and APIs.
I have also used tools like SQL, Python, and Excel to manipulate and analyze data.
I am comfortable working with both structured and unstructured data.
I have experience cleaning and transforming data to make it usable for analysis.
Q49. Whom are you going to query when you have TP discrepant data
I would query the relevant stakeholders involved in the data collection process.
Identify the stakeholders involved in the data collection process
Reach out to them to understand the data collection process and identify any potential issues
Collaborate with them to resolve the TP discrepant data
A marketing campaign is run, how will you decide metrics to be tracked
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