20+ Testhouse Interview Questions and Answers

Code 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

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

Create calculated fields in Tableau to dynamically adjust to changing table columns.

• Use calculated fields to reference specific columns by name instead of position.

• Utilize parameters to allow users to select which columns to display.

• Consider using custom SQL queries to dynamically adjust to changing table structure.

SQL joins are used to combine data from two or more tables based on a related column.

• Inner join returns only the matching rows from both tables

• Left join returns all rows from the left table and matching rows from the right table

• Right join returns all rows from the right table and matching rows from the left table

• Full outer join returns all rows from both tables

• Cross join returns the Cartesian product of both tables

Schemas are the blueprint of a database. There are three types of schemas - Physical, Logical, and View.

• Physical schema defines how data is stored in a database

• Logical schema defines the structure of the data in a database

• View schema defines how users view the data in a database

• Examples of physical schema include file systems, RAID, etc.

• Examples of logical schema include ER diagrams, UML diagrams, etc.

• Examples of view schema include views, reports, etc.

Heat maps display data in colors on a grid, while tree maps show hierarchical data using nested rectangles.

• Heat maps use colors to represent data values on a grid, while tree maps use nested rectangles to display hierarchical data.

• In Tableau, I have created heat maps to visualize sales data across different regions, and tree maps to show the sales distribution by product categories.

• Heat maps are useful for identifying patterns and trends in large datasets, while tree maps are...read more

Different types of graphs like bar charts, line graphs, and pie charts can help in visualizing KPIs effectively.

• Bar charts can be used to compare KPIs across different categories or time periods.

• Line graphs are useful for showing trends and changes in KPIs over time.

• Pie charts can display the proportion of each KPI relative to the total.

• Combination charts can be used to show multiple KPIs in a single graph for comparison.

Code to calculate average salary based on location

• Create a dictionary to store salaries based on location

• Calculate average salary for each location using the dictionary

• Return the average salaries for each location

Types of joins include inner join, left join, right join, and full outer join.

• Inner join: returns rows when there is a 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 in either table

Finding common elements in two lists.

• Use set intersection to find common elements.

• Iterate through both lists and compare elements.

• Sort both lists and use two pointers to find common elements.

Testing is needed to ensure the accuracy, reliability, and functionality of data analysis processes.

• Testing helps identify and prevent errors in data analysis processes.

• It ensures the accuracy and reliability of the results obtained from data analysis.

• Testing helps in validating the functionality of data analysis models and algorithms.

• It helps in identifying and fixing any issues or bugs in the data analysis process.

• Testing also helps in ensuring that the data analysis proces...read more

Logistic Regression is a statistical method used to analyze and model the relationship between a binary dependent variable and one or more independent variables.

• It is used to predict the probability of a binary outcome (0 or 1).

• It is a type of regression analysis that uses a logistic function to model the relationship between the dependent variable and independent variables.

• It is commonly used in fields such as healthcare, marketing, and finance.

• It can be used for both binary...read more

Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones.

• Start with two initial numbers, usually 0 and 1

• Add the two previous numbers to get the next number in the sequence

• Repeat this process to generate the Fibonacci series

HLOOKUP and VLOOKUP are functions in Excel used to search for a value in a table horizontally and vertically, respectively.

• HLOOKUP searches for a value in the first row of a table and returns a value in the same column from a specified row.

• VLOOKUP searches for a value in the first column of a table and returns a value in the same row from a specified column.

• Both functions are commonly used in Excel for data analysis and manipulation.

• Example: =HLOOKUP(lookup_value, table_array...read more

Conditional formatting is a feature in data analysis tools that allows users to apply formatting to cells based on specified conditions.

• Conditional formatting helps highlight important data points in a dataset

• Users can set rules for formatting, such as changing cell color based on value ranges

• It is commonly used in Excel, Google Sheets, and other spreadsheet programs

Window functions are a type of function in SQL that perform calculations across a set of table rows related to the current row.

• Window functions are used to perform calculations on a set of rows related to the current row.

• They allow you to perform calculations without grouping the rows into a single output row.

• Examples of window functions include ROW_NUMBER(), RANK(), and NTILE().

I would rate myself a 4 out of 5 in SQL proficiency.

• Proficient in writing complex SQL queries

• Experienced in optimizing database performance

• Familiar with data manipulation and analysis functions

• Comfortable working with large datasets

Back propagation is a technique used in neural networks to update the weights of the network by calculating the gradient of the loss function.

• Back propagation involves calculating the gradient of the loss function with respect to each weight in the network.

• The calculated gradients are then used to update the weights in the network in order to minimize the loss function.

• This process is repeated iteratively until the network converges to a set of weights that minimize the loss ...read more

Print Fibonacci sequence in Python

• Use a loop to generate Fibonacci numbers

• Start with 0 and 1 as the first two numbers

• Add the previous two numbers to get the next number

• Repeat the process until the desired sequence length is reached

Auditing is the process of evaluating and examining financial records to ensure accuracy and compliance with regulations.

• Auditing involves reviewing financial statements, transactions, and records.

• It helps identify errors, fraud, and areas for improvement in financial processes.

• Auditors provide an independent assessment of an organization's financial health and adherence to regulations.

• Examples of audits include internal audits, external audits, and tax audits.

SQL order of execution determines the sequence in which the different clauses in a SQL query are processed.

• SQL order of execution: FROM, WHERE, GROUP BY, HAVING, SELECT, ORDER BY.

• FROM: Specifies the tables involved in the query.

• WHERE: Filters the rows based on specified conditions.

• GROUP BY: Groups the rows based on specified columns.

• HAVING: Filters the groups based on specified conditions.

• SELECT: Retrieves the columns specified in the query.

• ORDER BY: Sorts the result set base...read more

RNN is a type of neural network that has connections feeding back into itself, allowing it to retain information over time. ANN does not have this capability.

• RNN has loops that allow information to persist, while ANN does not

• RNN is used for sequential data like time series or text, while ANN is used for static data

• RNN can handle variable input lengths, while ANN requires fixed input sizes

SQL execution order determines the sequence in which SQL statements are processed.

• 1. FROM and JOIN clauses are processed first to retrieve data from tables.

• 2. WHERE clause filters the rows based on specified conditions.

• 3. GROUP BY clause groups the rows based on specified columns.

• 4. HAVING clause filters the groups based on specified conditions.

• 5. SELECT clause retrieves the columns specified in the query.

• 6. ORDER BY clause sorts the result set based on specified columns.

• 7. L...read more

A subquery in SQL is a query nested within another query to retrieve data from multiple tables.

• Subqueries can be used in SELECT, INSERT, UPDATE, and DELETE statements.

• They can be correlated or non-correlated.

• Example: SELECT * FROM table1 WHERE column1 = (SELECT column2 FROM table2 WHERE condition);