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Hays Interview Questions

A/B Testing

Algorithms

Analytics

Machine Learning

Probability

Product Metrics

Python

Statistics

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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?

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?

In an A/B test, how can you check if assignment to the various buckets was truly random?

In an A/B test, which of the following is a common method to determine if the assignment to the test groups was truly random?

In an A/B test, which of the following is a common method to determine if the assignment to the test groups was truly random?

Random Bucketing

A/B Testing & Experimentation

Your new company A leading technology consultancy with over 60 years of history and with presence in more than 50 countries. They work with a variety of organisations to help with their AI, technology and people-focused transformation needs. Leveraging capabilities across strategy, technology, design, engineering and business operations. They are looking to bring in Transformation consultants to help to grow and drive their ServiceNow practice. This is a unique opportunity to be part of a forward-thinking team, shaping the future of work by delivering solutions that address today's challenges and anticipate tomorrow's needs. Your new role As a ServiceNow Transformation Consultant, you will work closely with a variety of organisations to understand their business needs, optimise HR processes and deliver tailored ServiceNow HRSD capabilities that improve operational efficiency and elevate employee engagement across the lifecycle. You will contribute to project delivery by translating business requirements into functional specifications, enabling the configuration of ServiceNow modules and supporting testing and deployment activities. Your insights will help clients unlock the full potential of digital HR through automation, AI, and data-driven decision-making. Key Responsibilities:<ul><li>Facilitate process workshops to map out current-state and future-state journeys (e.g., onboarding, offboarding, case management).</li><li>Collaborate with stakeholders to identify pain points and opportunities for automation using ServiceNow HRSD.</li><li>Design and deliver ServiceNow solutions that underpin and enable improved HR service delivery, employee communications, and organisational effectiveness.</li><li>Lead workstreams such as process design, configuration, testing, and deployment.</li><li>Translate business requirements into ServiceNow system capabilities, ensuring alignment with HR strategy and user experience goals.</li><li>Work with cross-functional teams to ensure successful implementation and adoption of ServiceNow solutions.</li><li>Support change management, communication planning, and stakeholder engagement to drive transformation outcomes.</li><li>Contribute to internal initiatives such as proposition development, AI readiness and adoption, thought leadership, and practice growth.</li><li>Mentor junior consultants and support their development.</li></ul>What you'll need to succeed<ul><li></li><li>Experience in HR process design, workshops, and stakeholder engagement.</li><li>Strong understanding of or experience of working in HR or GBS operational environments.</li><li>Experience of how ServiceNow HRSD supports and delivers HR services (e.g., onboarding, lifecycle events, case management).</li><li>Familiarity with ServiceNow maturity assessments and discovery.</li><li>Strong awareness of ServiceNow HRSD AI and automation capabilities, and integrations to people technology and collaboration tools.</li><li>Ability to map out HR processes and design technology-enabled solutions.</li><li>Familiarity with collaboration tools and techniques for process improvement.</li><li>Consulting experience in HR transformation programmes, ideally within a major consultancy or similar environment.</li><li>Strong communication and organisational design skills.</li><li>Exposure to agile delivery methods and integration tools (desirable).</li><li>Experience of using data and analytics to drive continuous improvement.</li><li>ServiceNow Implementation Specialist CIS - HRSD Certified (preferable).</li><li>Security Clearance nice to have</li></ul>What you'll get in return Basic salary of £45-55K + benefits Opportunity to join a leading technology transformation consultancy and help to grow this key practice Build on your ServiceNow knowledge and acquire transformation experience What you need to do now If you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or call us now. If this job isn't quite right for you, but you are looking for a new position, please contact us for a confidential discussion about your career. Hays Specialist Recruitment Limited acts as an employment agency for permanent recruitment and employment business for the supply of temporary workers. By applying for this job you accept the T&C's, Privacy Policy and Disclaimers which can be found at hays.co.uk

Your New Company Join a cutting-edge engineering organisation at the forefront of advanced manufacturing and propulsion technologies. With a global footprint and a strong UK base, this venture-backed company is pioneering the development of high-performance microturbine engines using proprietary materials and additive manufacturing techniques. You'll be part of a multidisciplinary team of engineers, scientists, and software developers working on next-generation solutions for jet propulsion. Your New Role As an Experimental Data Engineer, you'll play a key role in building, maintaining, and optimising engine test rigs and data acquisition systems. Reporting to the Testing Lead, you'll collaborate closely with design and experimental teams to validate new components and control systems. Your work will directly influence the performance and scalability of innovative propulsion technologies.You'll be primarily based at the company's manufacturing site in Yarnton, with occasional travel to nearby testing facilities. A competitive salary and equity incentives are offered. Key Responsibilities:<ul><li>Develop and maintain LabVIEW-based data acquisition systems using NI DAQ hardware</li><li>Support data post-processing and analysis (e.g. Python)</li><li>Investigate and implement new sensor technologies</li><li>Automate workflows for data capture and processing</li><li>Maintain clean code practices and version control in collaborative environments</li><li>Work cross-functionally to ensure experimental feasibility and infrastructure readiness</li></ul> What You'll Need to Succeed Essential:<ul><li>1-3 years of industry experience in experimental data capture, or equivalent PhD experience</li><li>Proficiency in LabVIEW or similar data acquisition platforms</li><li>Strong understanding of hardware/software integration for high-speed, high-temperature systems</li><li>Degree in mechanical, aeronautical, or related engineering/STEM discipline</li><li>Experience with collaborative coding (e.g. Python, C, Git)</li><li>Excellent problem-solving, communication, and organisational skills</li></ul>Desirable:<ul><li>Full LabVIEW system design experience (front-end and back-end)</li><li>Basic electrical and electronics knowledge, including circuit design</li><li>Experience with embedded electronics (e.g. Arduino, STM32)</li><li>UX design for control systems and data visualisation</li></ul> What you need to do now If you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or call us now. If this job isn't quite right for you, but you are looking for a new position, please contact us for a confidential discussion about your career. Hays Specialist Recruitment Limited acts as an employment agency for permanent recruitment and employment business for the supply of temporary workers. By applying for this job you accept the T&C's, Privacy Policy and Disclaimers which can be found at hays.co.uk

???? We’re Hiring: Data Engineer (Azure) – Porto, Portugal (Hybrid)Are you passionate about building scalable data solutions and working with cutting-edge cloud technologies? Join a leading name in Automotive Technology and help shape the future of data-driven innovation. Job Title: Data Engineer (Azure)Sector: Automotive TechnologyLocation: Porto, Portugal (Hybrid)Languages: English (Fluent) & Portuguese-Nice to have About the RoleWe are looking for an experienced Data Engineer to join our team in Porto. This role involves designing and maintaining scalable data solutions in a dynamic automotive technology environment. Key Responsibilities<ul><li>Design, build, and maintain data ingestion, transformation, and delivery pipelines using Azure.</li><li>Work with structured and unstructured data from multiple sources.</li><li>Ensure efficiency, scalability, and reliability of data solutions.</li><li>Collaborate with analysts and data scientists to make data accessible and analysis-ready.</li><li>Implement best practices for data quality, lineage, and security.</li><li>Develop monitoring tools and alerts for seamless pipeline operations.</li><li>Maintain clear documentation of data architectures and technical decisions.</li></ul> Key Skills & Experience<ul><li>Proven experience as a Data Engineer in cloud environments, especially Microsoft Azure.</li><li>Hands-on experience with:</li><li>Azure Data Factory, Synapse Analytics, Data Lake Storage Gen2</li><li>Azure SQL Database, Databricks, Azure DevOps (CI/CD)</li><li>Proficient in SQL and Python; knowledge of Scala or Apache Spark is a plus.</li><li>Strong analytical skills and attention to detail.</li><li>Comfortable working in agile, cross-functional teams.</li></ul> ???? Interested?Connect with me on LinkedIn or apply directly via email: deepshikha.jain3@hays.com

Hays Solutions, società del gruppo multinazionale Hays, quotata al London Stock Exchange, offre servizi di consulenza mirati all’individuazione, alla comprensione e al raggiungimento degli obiettivi concreti di un progetto di business in ambito IT, Engineering o Digital. Siamo alla ricerca di un Senior Software Engineer da inserire nel nostro team. Responsabilità principali: <ul><li>Definire e proporre soluzioni tecnologiche in linea con gli obiettivi del progetto.</li><li>Supportare il team nello sviluppo e nella risoluzione di problematiche tecniche.</li><li>Collaborare con il cliente per comprendere esigenze e tradurle in soluzioni software.</li><li>Essere operativo sul codice, mantenendo una visione d’insieme.</li></ul> Requisiti: <ul><li>Java 1.8+</li><li>Spring, Springboot</li><li>Docker</li><li>MySql, MongoDB</li><li>RESTful Api</li><li>Kubernetes</li><li>Tecnologie e strumenti open source</li><li>JPA</li><li>Hibernate</li></ul> Modalità di lavoro: Ibrido - Milano Cosa devi fare:Se sei interessato a questa opportunità, clicca su "Candidarsi ora". Se questa opportunità non è in linea con le tue aspettative, ma sei alla ricerca di un nuovo lavoro, visita il nostro sito Internet per scoprirne di nuove. I candidati di ambo i sessi, dopo aver visionato l'informativa obbligatoria sulla privacy sul sito www.hays-itservices.it, sono pregati di inviare il proprio CV. Hays Solutions S.r.l. con Socio unico. Soggetta a direzione e coordinamento da parte di Hays Plc.

Job Title: Senior Business AnalystLocation: Montreal, QC (Onsite – 4 days/week) Duration: [Star from 6+ Month] possibility of extension Language Requirement: Bilingual (English & French) Role OverviewWe are seeking a Senior Business Analyst to lead the requirements gathering and process mapping for the replacement of Microsoft Project Online with a new project management solution. This role involves close collaboration with multiple business units, vendor selection, and ensuring strategic alignment throughout the project lifecycle. Key Responsibilities<ul><li>Facilitate workshops with various business units for requirement elicitation, process mapping, and gap analysis.</li><li>Develop and maintain documentation including requirements traceability, process models (BPMN, UML), and RFP content.</li><li>Support vendor selection and qualification, ensuring alignment with organizational goals and strategy.</li><li>Coordinate User Acceptance Testing (UAT) and assist with system configuration and testing as needed.</li><li>Engage stakeholders effectively, both internal and external, and lead meetings with large audiences.</li></ul> Must-Have Skills (Non-Negotiables)<ol><li>Business Analysis Expertise: </li></ol><ul><li>Prioritization, requirement traceability, process modeling (BPMN, UML).</li></ul><ol><li>Strategic Alignment & Vendor Selection: </li></ol><ul><li>Experience building RFPs, evaluating vendor alignment with organizational goals.</li></ul><ol><li>Stakeholder Engagement & Soft Skills: </li></ol><ul><li>Strong facilitation skills, autonomy, ability to lead workshops and meetings confidently.</li></ul> Technical Skills<ul><li>Proficiency in Microsoft Office Suite.</li><li>Familiarity with project management tools (Planner, MS Project, other PPM solutions).</li><li>Experience with diagramming tools (Visio or similar).</li><li>CBAP certification is an asset.</li></ul> Experience Required<ul><li>10+ years as a Business Analyst with end-to-end project lifecycle experience.</li><li>Strong documentation and communication skills.</li></ul> Day-to-Day Activities<ul><li>Conduct workshops for requirements gathering and process mapping.</li><li>Perform gap analysis and coordinate UAT.</li><li>Prepare and manage project documentation.</li><li>Collaborate with stakeholders and vendors throughout the project.</li></ul> Interview Process<ul><li>1–2 rounds focusing on technical expertise, soft skills, and past experience.</li></ul>

Data Scientist - Data Analysis -Machine Learning - Python - Forecasting - Big DataLa tua nuova aziendaLa nostra azienda cliente è una società di consulenza specializzata: copre i servizi operativi, l’esecuzione del progetto e le competenze tecniche all’interno dell’intera catena del valore nel settore energetico.Con un approccio unico e trasversale, aiuta i clienti a raggiungere obiettivi impegnativi e trovare nuove opportunità di business, guidandoli attraverso la transizione energetica grazie al suo team polivalente di esperti con lunga esperienza sui principali mercati europei nel settore energetico retail e wholesale. Il tuo nuovo ruoloA diretto riporto del Senior Data Manager, in ottica di implementazione del team, siamo alla ricerca di un Data Scientist che sia specializzata in forecasting e modelli di ottimizzazione. Nel caso specifico, il candidato di occuperà di:<ul><li>Supporto alla creazione di modelli di ottimizzazione e algoritmi previsionali short-term per la gestione degli impianti nei mercati spot e dei servizi;</li><li>Supporto alla definizione delle strategie di arbitraggio e ottimizzazione della produzione degli impianti di generazione (eolici, fotovoltaici, batterie, idroelettrico fluente);</li><li>Supporto alla creazione di algoritmi per la previsione dei consumi;</li><li>Supporto per elaborazione e analisi big data (meteo, producibilità, prezzi);</li><li>Supporto per il monitoraggio delle performance degli impianti rinnovabili;</li><li>Elaborazione report e analisi dei risultati dei modelli implementati.</li></ul> Di cosa hai bisogno per aver successoRicerchiamo figure che abbiamo almeno un’esperienza di 1-2 anni in un ruolo similare con le seguenti caratteristiche:<ul><li>Conoscenza avanzata di modelli di Machine Learning;</li><li>Conoscenza avanzata di Python (o altro linguaggio di programmazione);</li><li>Conoscenza di Excel e/o di uno strumento di Business Intelligence (Power BI, Qlik Sense, Tableau)</li></ul> Cosa avrai in cambioEntrerai a far parte di una realtà solida e con grandi ambizioni, guidata da persone con esperienza. Avrai la giusta autonomia per gestire al meglio le attività e guidare nel giusto modo il tuo team.Sede di lavoro: Milano/Roma; buona flessibilità lato smart working

We are currently working with a global financial services organisation on the recruitment of a project manager on an 11-month contract with the possibility of extension. You will join a newly formed team to implement policies and procedures that go along with the management of human capital risk. As a risk and control lead, you will be required to design, develop and implement Human Capital Risk (HCR) requirements for the organisation. This role will work on a range of activities to implement standards and consistent practices for HCR risk and control management in compliance with firm-wide requirements. Responsibilities include:<ul><li>Develop and execute Inherent Risk assessments tailored to the HCR risks and Markets businesses</li><li>Understand Manager Control Assessments (MCA) data, identify deficiencies and work across business and markets stakeholders to remediate</li><li>Define and drive the implementation of standardized HCR controls and monitoring</li><li>Work with markets stakeholders to understand risks and required controls across businesses</li><li>Standardize HCR Reporting. Identify different data sources and assess methodologies to make recommendations for markets </li></ul> Essential Criteria<ul><li>At least 5 years operating as a PM/BA in an enterprise environment</li><li>Understanding of operational risk management frameworks</li><li>An in-depth knowledge of threats, risks and controls (preferably specific to financial)</li><li>A proven ability to apply business understanding to developing robust risk and control policies and procedures</li><li>Strong collaboration and problem-solving skills </li><li>Ability to interpret and synthesize complex information and data into actionable insights</li><li>Proven ability to proactively identify opportunities to optimise and streamline processes, propose solutions and lead implementation of improvements</li></ul> This role will be 3 days working from the office in Belfast. Only candidates with the ability to fulfil this will be considered. Although the role is initially for an 11-month period, there is a high possibility of permanency or extension. If you're interested in this role, please forward an up-to-date copy of your CV If this job isn't quite right for you, but you are looking for a new position, please contact us for a confidential discussion about your career. Hays Specialist Recruitment Limited acts as an employment agency for permanent recruitment and employment business for the supply of temporary workers. By applying for this job you accept the T&C's, Privacy Policy and Disclaimers which can be found at hays.co.uk

About the roleAs a Senior Product Manager- Supply Chain, for clients AI Team to spearhead the strategy, rollout, and impact of multiple cutting-edge AI products, each designed to boost MRO supply chain performance across all client airlines.Tell me more, tell me more…Our client is currently looking for a new recruit in joining their team, please read on! You can also ask our friendly recruitment team any questions you may have about the role, between 8:30am-5:30pm Monday to Friday. Shifts: Monday – Friday (37.5 hours per week)What You’ll Do: <ul><li>Drive Product Success: Oversee the full lifecycle of multiple AI solutions, ensuring they deliver measurable value and adoption across the Group.</li><li>Maximise Impact: Accelerate productivity and cost savings, securing material commitments from each airline</li><li>Influence & Align: Build consensus and drive change among diverse stakeholders, overcoming barriers to group-wide adoption.</li><li>Shape Strategy: Set product vision, prioritise features, and ensure the suite stays ahead of industry benchmarks</li></ul>What You Bring:<ul><li>Product Leadership: Proven experience in product management, ideally in AI, aviation (specifically MRO), or complex enterprise tech.</li><li>Stakeholder Influence: Exceptional ability to drive consensus and manage competing priorities across business units.</li><li>Execution Excellence: Track record of delivering results in high-velocity, transformation-driven environments.</li><li>Technical Acumen: Strong grasp of AI/ML concepts and their application to operational optimisation.</li><li>Communication: Clear, compelling communicator—able to engage execs, engineers, and frontline teams alike.</li></ul> Experience & Skills<ul><li>Commercial and delivery accountability for digital product at a leading consultancy (e.g. as part of a client engagement); or within a recognised leading organisation</li><li>Has worked as a consultant or colleague within FTSE100 organisations or equivalent</li><li>Intrapreneurial experience desirable </li></ul> What’s in it for you? – Our client loves to reward their people for doing a great job.<ul><li>This is a 6-month contract(possibility to extend).</li><li>A day rate, in-scope IR35.</li><li>This role provides a hybrid working access from the comforts of your own home and only going to our state-of-the-art office in Waterside (2/3) days per week, also weekly international travel may required </li></ul>Next StepsOnce you’ve applied, one of our friendly recruitment consultants will give you a call and talk you through the screening process. If your application is successful, you’ll be involved in a live virtual interview with one of our client’s hiring managers to get to know you better.We look forward to speaking to you!

Your new company Working for a globally renowned retail company. Your new role Seeking a hands-on Data Science role in London to support R&D for automated packaging. You'll combine operations research, simulation, and practical engineering to create models that improve how the products are counted, bagged, and boxed. The goal: deliver iterative, production-ready solutions that make our packaging systems faster, smarter, and more reliable. What you'll need to succeed Not the classic "predictive modeling" skillset. Required skillset:<ul><li>Exploration vs. exploitation mindset.</li><li>Ability to search optimal recipe space within a model.</li><li>Build models to explore and exploit possibilities, not just predict outcomes!</li><li>Operations research: handling constraints, finding optimal arrangements for fastest packing.</li><li>Stochastic simulation: accounting for variability in machine speeds and conveyor setups.</li><li>Techniques: statistical simulation, stochastic modeling, linear optimization.</li></ul>Tools & Platforms Expertise:<ul><li>Databricks for data workflows.</li><li>GitHub for CI/CD and version control.</li><li>Package management for reproducibility.</li></ul> What you'll get in return Flexible working options available. What you need to do now If you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or call us now. Hays Specialist Recruitment Limited acts as an employment agency for permanent recruitment and employment business for the supply of temporary workers. By applying for this job you accept the T&C's, Privacy Policy and Disclaimers which can be found at hays.co.uk

About the Role:Join the Media & Advertising team supporting digital and agency integrations (e.g., YouTube, Meta) for advertiser campaigns. You’ll lead end-to-end ML solution development focused on ad performance and audience targeting.Key Responsibilities:<ul><li>Build and deploy ML models for Click-Through Rate (CTR) prediction, time series forecasting, and budget optimization</li><li>Maintain and enhance audience lookalike models</li><li>Design and implement A/B testing frameworks</li><li>Collaborate with cross-functional teams to deliver scalable ML solutions</li></ul>Tech Stack:<ul><li>Cloud: GCP (preferred), AWS or Azure also acceptable</li><li>ML Tools: Vertex AI, Amazon SageMaker</li><li>Languages: Python, Go</li><li>Other: SQL, Fast API, LLMs (nice to have)</li></ul>Ideal Candidate:<ul><li>Experienced ML Engineer with strong end-to-end deployment skills</li><li>Hands-on with CTR modelling, forecasting, and ad relevancy</li><li>Comfortable working in a fast-paced, product-driven environment</li><li>Strong coding and problem-solving skills</li></ul>

Question	Topic	Difficulty	Ask Chance
Boarding Times Bias	Statistics	Medium	Very High
Hundreds of Hypotheses	Statistics	Medium	Very High
Random Bucketing	A/B Testing & Experimentation	Medium	Very High

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