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Duolingo Interview Questions

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You are testing hundreds of hypotheses with many t-tests. What considerations should be made?

What is a key disadvantage of the F-test when compared to multiple t-tests?

What is a key disadvantage of the F-test when compared to multiple t-tests?

Hundreds of Hypotheses

You are testing hundreds of hypotheses with many t-tests. What considerations should be made?

Let’s say that your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value.

How would you assess the validity of the result?

Experiment Validity

Suppose there exists a new airline named Jetco that flies domestically across North America. Jetco recently had a study commissioned that tested the boarding time of every airline, and it came out that Jetco had the fastest average boarding times of any airline.

What factors could have biased this result, and what would you look into?

What could potentially bias the average boarding time in favor of an airline that only flies domestically?

What could potentially bias the average boarding time in favor of an airline that only flies domestically?

Boarding Times Bias

A new airline came out as the fastest average boarding times compared to other airlines.  What factors could have biased this result and what would you look into?

Duolingo Salaries by Position

Our mission at Duolingo is to develop the best education in the world and make it universally available. But weve got more left to do and thats where you come in! Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are passionate about educating our users, making fact-based decisions, and finding innovative solutions to complex problems. We offer meaningful work, limitless learning opportunities, and collaboration with world-class minds. Come brighten your life and over half a billion more! As a Backend Engineer you will work on building the APIs that power our products and give our learners a best-in-class experience. Our microservices infrastructure is composed of hundreds of endpoints serving hundreds of millions of requests per day. You will partner with your team members on identifying requirements and designing services that are fast, resilient, and cost effective. You will have ownership over the entire lifecycle of your services and associated infrastructure, and ensure they are always operating well. <h5>Read about the technical problems our Engineers work on </h5> <h5>Below you can find more information about teams we're hiring for </h5>Architecture Team: <ul><li>The Architecture teams mission is to ensure that Duolingos software continues to scale as we grow. We work on some of the largest and most critical infrastructure run by Duolingo and provide tools and best practice guidance to teams as they look to create new features and services. In this role, you will lay the groundwork for the future success of Duolingos software platforms. </li> </ul>Music Team: <ul><li>As a Backend engineer on the Music team, you will help build the technology that changes how people around the world learn Music. The features that you ship will help learners to develop core music skills like sight reading and ear training in a fun, engaging way. </li> </ul>DET Test Scoring Team: <ul class="p-rich_text_list p-rich_text_list__bullet"><li>As an engineer on the Scoring team for the Duolingo English Test, you will help advance the state of the art in language testing. You will work closely with AI researchers and assessment scientists to pioneer innovative and AI-driven ways to assess language ability, while maintaining critical infrastructure and strengthening the tests reliability. You will advance the teams mission to lower barriers and increase opportunities for English language learners everywhere. </li> </ul>DET Proctoring Operations Team: <ul class="p-rich_text_list p-rich_text_list__bullet"><li>The Proctoring Operations teams mission is to ensure that we provide high-quality and efficient human proctoring for all Duolingo English Test tests. In this role, you will take on full-stack web development work. You will primarily work on the proctor portal an in-house tool used by contractors for proctoring the test. You will also work closely with the anti-cheating team to take new signals developed by them and put them in the hands of proctors. </li> </ul>Data Infrastructure Team: <ul class="p-rich_text_list p-rich_text_list__bullet"><li>As a Backend engineer on the Data Infrastructure team, you will build and maintain critical infrastructure for ingestion, storage, and visualization of all of Duolingo's data (that's billions of items of data each day!). </li> </ul>Learning Scaling Area: <ul><li>The Learning Scaling Areas mission is to ensure that all of Duolingos learners have access to high-quality educational content. We leverage pedagogical experts and AI to create content for over 100 courses. You will be responsible for building and improving the infrastructure and tooling that drives content creation. </li> </ul>Learning R&D Area: <ul><li>The Learning R&D Area works on improving the learning experience of our users with new bets, technologies, and features, that fill the learning gaps in our product. Our goal is to make Duolingo the best way to level up your language skills, regardless of your proficiency level. </li> </ul><h5>Responsibilities </h5><ul><li>Collaborate on software projects with product design and backend aspects </li><li>Develop, release, and maintain backend services and/or infrastructure </li><li>Lead individual project priorities, milestones, and ensure we're always shipping </li> </ul><h5>Requirements </h5><ul><li>A Bachelors degree in Computer Science or related technical field </li><li>Strong competencies in data structures, algorithms, and software design </li><li>Experience programming in Java, Python, or Kotlin </li><li>Solid understanding of one or more database technologies </li> </ul><h5>Exceptional candidates will have </h5><ul><li>Industry experience building high-traffic APIs using public cloud providers </li> </ul>We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice. We post a multi-level salary range for all of our roles. This is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. Salary Range: $148,800$274,600 USD

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are passionate about educating our users, making fact-based decisions, and finding innovative solutions to complex problems. We offer meaningful work, limitless learning opportunities, and collaboration with world-class minds. Come brighten your life and over half a billion more! We're looking for a Senior Data Scientist to join our Data Science & Analytics team. You will be responsible for understanding how changes in our most granular metrics impact our top-line business performance, then concisely communicating those insights to senior company leaders. You will also work closely with engineering teams and product managers to harness that understanding and improve the app through experimentation. By working cross-functionally to empower our partners with empirical insights, you will drive real change and measurable impact for Duolingo every day. Responsibilities <ul><li>Collaborate with cross-functional teams to gather, integrate, and analyze data from various sources.</li><li>Lead analytics solutions end-to-end, including project management, data gathering and manipulation, modeling, problem-solving, and communication of insights and recommendations.</li><li>Build engaging and informative dashboards using visualization tools (e.g., Sigma, Tableau, Plotly), and use these tools to analyze trends and make recommendations.</li><li>Run periodic business reviews to keep senior leadership updated on how the company is operating from a bottoms-up view, and perform deep-dive analyses to understand the underlying causes.</li><li>Use business review insights to pinpoint growth opportunities, then drive that growth via product experiments and changes.</li><li>Mentor and guide junior data scientists in developing their analytical skills and communication.</li></ul>Requirements <ul><li>Bachelor's degree in a relevant field (e.g., Data Science, Economics, Business Analytics, Information Systems).</li><li>5+ years of experience in data science, business intelligence, or related roles.</li><li>Experience in programming (e.g., Python, R) to extract, transform, clean, and analyze large amounts of data.</li><li>Advanced SQL skills to build datasets that enable ad-hoc analyses and efficient visualization.</li><li>Expertise in data visualization tools such as Sigma, Tableau, or Looker for full-stack data analysis, insight synthesis, and presentation.</li><li>Outstanding problem-solving abilities and the capacity to distill complex data into concise explanations and actionable insights.</li><li>Excellent verbal and written communication skills with the ability to collaborate effectively with both technical and non-technical partners.</li><li>Able to relocate to and work in our New York or Pittsburgh office.</li></ul>Bonus Points <ul><li>Master's degree in data science, economics, statistics, or an equivalent quantitative field</li><li>Experience managing, analyzing and communicating results to senior leadership</li><li>Experience training machine learning models and deploying them in production</li><li>Experience at a high-growth company that has undertaken an IPO</li><li>An impressive Duolingo XP or streak!</li></ul> We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice. We post a multi-level salary range for all of our roles. This is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. Salary Range: $169,700-$220,400 USD

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! We are looking for an experienced, entrepreneurial-minded Product Manager who can push our product forward and values moving quickly. This job description represents different full-time roles across Duolingo. Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are passionate about educating our users, making fact-based decisions, and finding innovative solutions to complex problems. We offer meaningful work, limitless learning opportunities, and collaboration with world-class minds. Come brighten your life and over half a billion more! Responsibilities: <ul> <li>Drive product features through their entire creative cycle: ideation, specification, development, release, analysis, and iteration </li><li>Establish the product vision and strategy for your product area, and build alignment across product teams, cross-functional partners, and leadership team </li><li>Perform qualitative and quantitative research to explore and validate feature ideas </li><li>Partner with product designers to ensure a fun and delightful user experience in our product </li><li>Work with engineers to help guide feature development </li><li>Perform experiment analysis on features and find opportunities for optimization </li><li>Define your key performance indicator(s) that drive company goals, and achieve them! </li></ul>Requirements: <ul> <li>A desire to make the world a better place through technology and education </li><li>Ability to apply user insights, data, and statistical analyses to inform decisions </li><li>An instinct for creating simple and intuitive user experiences </li><li>Demonstrated ability to be resourceful, curious, and innovative </li><li>Experience leading projects and teams </li><li>Bachelor's Degree in Engineering, Business, Design, Psychology, or equivalent </li></ul>Exceptional candidates will have: <ul> <li>Advanced degree in Business, Computer Science, Design, Psychology, or equivalent </li><li>Extensive experience in fast-growing, consumer-facing apps that have strong IAP and/or subscription growth. </li></ul> We post a multi-level salary range for all of our roles. The multi-level salary range for this role is $148,800 - $274,600 and is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice.

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! We are looking for an experienced, entrepreneurial-minded Product Manager who can push our product forward and values moving quickly. Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are looking for a math enthusiast who can marry their understanding of core math concepts, with their passion for leveraging technology to build meaningful mathematical learning experiences. You will join our Math team to help us deliver the best education in the world through evidence-based practices. Join Duolingo to feel empowered as an educator, impacting millions of learners. Responsibilities: <ul> <li>Drive product features through their entire creative cycle: ideation, specification, development, release, analysis, and iteration </li><li>Establish the product vision and strategy for your product area, and build alignment across product teams, cross-functional partners, and leadership team </li><li>Perform qualitative and quantitative research to explore and validate feature ideas </li><li>Partner with product designers to ensure a fun and delightful user experience in our product </li><li>Work with engineers to help guide feature development </li><li>Perform experiment analysis on features and find opportunities for optimization </li><li>Define your key performance indicator(s) that drive company goals, and achieve them! </li></ul>Requirements: <ul> <li>Passion for math and an understanding of math fundamentals </li><li>4-6 years of product management experience with a proven track record </li><li>A desire to make the world a better place through technology and education </li><li>Ability to apply user insights, data, and statistical analyses to inform decisions </li><li>An instinct for creating simple and intuitive user experiences </li><li>Demonstrated ability to be resourceful, curious, and innovative </li><li>Experience leading projects and teams </li><li>Bachelor's Degree in Engineering, Business, Design, Psychology, or equivalent </li></ul>Exceptional candidates will have: <ul> <li>Advanced degree in Business, Computer Science, Design, Psychology, or equivalent </li><li>Extensive experience in fast-growing, consumer-facing apps that have strong IAP and/or subscription growth. </li></ul> We post a multi-level salary range for all of our roles. The multi-level salary range for this role is $148,800 - $274,600 and is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice.

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are passionate about educating our users, making fact-based decisions, and finding innovative solutions to complex problems. We offer meaningful work, limitless learning opportunities, and collaboration with world-class minds. Come brighten your life and over half a billion more! As an Engineering Manager at Duolingo, you will have the opportunity to grow as both a software engineer and an engineering leader. In this role, you'll join Duolingo's rapidly growing engineering organization to lead mission critical projects from end to end, contribute to product strategy and lead a team of world-class engineers. More information on the team: Monetization Area: <ul><li>The Monetization Area focuses on Duolingo's key business drivers-subscriptions, ads, and in-app purchases. Our area's goal is to build the best premium experiences for our learners while ensuring the sustainability and success of our business model. You will play an instrumental role in the strategic direction of Duolingo by developing and refining the methods that make our monetization efforts more effective and efficient. </li></ul>Math Team Area: <ul> <li>The Math team creates software to help adult learners overcome math anxiety and realize that math can be fun. We want to do for math what Duolingo has already done for language: Create the best education in the world and make it universally available. </li></ul>You Will... <ul> <li>Lead and develop a team of software engineers, including task planning, technical leadership and career development of your reports. </li><li>Own the overall planning, execution and success of projects that directly improve our top-line business metrics. </li><li>Lead the development of new features and/or microservices in an innovative and fast-paced environment. </li><li>Collaborate with product teams across the company to find new imaginative opportunities to increase company business metrics, like DAUs, revenue, retention and app performance. </li><li>Identify best practices and tools to maximize our ability to build and maintain features and services. </li></ul>You Have... <ul> <li>Experience in guiding a software engineering team and setting technical direction. </li><li>Experience in leading cross-functional software engineering projects. </li><li>Strong written and verbal communication skills. </li><li>B.A./B.S. in Computer Science or a related field </li></ul>Exceptional Candidates Will Have... <ul> <li>Experience in fast-growing, consumer-facing, data-driven startups, ideally mobile app based. </li><li>Master's degree or PhD in Computer Science or a related field. </li></ul> We post a multi-level salary range for all of our roles. The multi-level salary range for this role is $174,900 - $335,600 and is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice.

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! We are looking for an experienced, entrepreneurial-minded Product Manager who can push our product forward and values moving quickly. Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are looking for a math enthusiast who can marry their understanding of core math concepts, with their passion for leveraging technology to build meaningful mathematical learning experiences. You will join our Math team to help us deliver the best education in the world through evidence-based practices. Join Duolingo to feel empowered as an educator, impacting millions of learners. Responsibilities: <ul><li>Drive product features through their entire creative cycle: ideation, specification, development, release, analysis, and iteration</li><li>Establish the product vision and strategy for your product area, and build alignment across product teams, cross-functional partners, and leadership team</li><li>Perform qualitative and quantitative research to explore and validate feature ideas</li><li>Partner with product designers to ensure a fun and delightful user experience in our product</li><li>Work with engineers to help guide feature development</li><li>Perform experiment analysis on features and find opportunities for optimization</li><li>Define your key performance indicator(s) that drive company goals, and achieve them!</li></ul>Requirements: <ul><li>Passion for math and an understanding of math fundamentals</li><li>4-6 years of product management experience with a proven track record</li><li>A desire to make the world a better place through technology and education</li><li>Ability to apply user insights, data, and statistical analyses to inform decisions</li><li>An instinct for creating simple and intuitive user experiences</li><li>Demonstrated ability to be resourceful, curious, and innovative</li><li>Experience leading projects and teams</li><li>Bachelor's Degree in Engineering, Business, Design, Psychology, or equivalent</li></ul>Exceptional candidates will have: <ul><li>Advanced degree in Business, Computer Science, Design, Psychology, or equivalent</li><li>Extensive experience in fast-growing, consumer-facing apps that have strong IAP and/or subscription growth.</li></ul> We post a multi-level salary range for all of our roles. The multi-level salary range for this role is $148,800 - $274,600 and is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice.

Our mission at Duolingo is to develop the best education in the world and make it universally available. But we've got more left to do - and that's where you come in! Duolingo is the world's most popular learning app. Beyond our core learning product, we also offer English proficiency testing with the Duolingo English Test, and are bringing new subjects into the Duolingo app, where people can develop their Math and Music skills. We are passionate about educating our users, making fact-based decisions, and finding innovative solutions to complex problems. We offer meaningful work, limitless learning opportunities, and collaboration with world-class minds. Come brighten your life and over half a billion more! We're looking for an experienced Platform Product Manager to increase the security of Duolingo English Test. You will lead the development of an innovative testing platform using the latest Machine Learning & AI technologies aimed at creating a secure test environment. The Duolingo English Test is one of our fastest growing businesses at Duolingo. With over 5,000 partner institutions, we are disrupting the high-stakes language-assessment market. Students can take our test from home because it is proctored through AI-based technology. The Duolingo English Test saves students time and money, allowing partner institutions to provide a better experience to their students and to gain access to a more diverse applicant pool. If you love making a difference in the world through technology, this is the place for you. You Will... <ul> <li>Build features that enhance the security and authenticity of the test </li><li>Collaborate with a team of AI researchers and engineers building new AI-powered feature </li><li>Partner with product designers to ensure a delightful user experience while considering trade-offs to increase test security </li><li>Work with executive leadership to drive product strategy for the Duolingo English Test </li><li>Drive product features through their entire creative cycle: ideation, specification, development, release, analysis, and iteration </li><li>Perform qualitative and quantitative research to explore and validate feature ideas </li><li>Be responsible for hitting the key performance indicators you are entrusted with </li></ul>You Have... <ul> <li>5+ years of product management or related industry experience </li><li>Experience building AI or video related products </li><li>Experience leading projects and teams </li><li>Ability to apply user insights, data, and statistical analyses to inform decisions </li><li>An instinct for creating simple and intuitive user experiences </li><li>Demonstrated ability to be resourceful, curious, and innovative </li><li>A desire to make the world a better place through technology and education </li><li>Bachelor's Degree in Engineering, Business, Design, Psychology, or equivalent </li></ul>Exceptional Candidates Will Have... <ul> <li>Advanced degree in Business, Computer Science, Design, Psychology, or equivalent </li><li>Understanding of machine learning concepts, frameworks, and best practices </li></ul> We post a multi-level salary range for all of our roles. The multi-level salary range for this role is $148,800 - $274,600 and is not inclusive of the rest of our awesome portfolio that includes equity compensation and world-class benefits. Our salary ranges are the same for all US locations. Your recruiter can share more details about the range for a specific level during the hiring process. The actual salary within the range is determined by many factors including but not limited to, skills, experience, education, and internal equity. We will do everything we can within reason to make sure that your interview takes place in an environment that fairly and accurately assesses your skills. If you need assistance or accommodation, please contact your recruiter. Take a peek at how we care for our employees' holistic well-being with our benefits here. Duolingo is proud to be an Equal Employment Opportunity employer. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. By applying for this position your data will be processed as per the Duolingo Applicant Privacy Notice.

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