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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?

Let’s say we have a table with an <code>id</code> and <code>name</code> fields. The table holds over 100 million rows and we want to sample a random row in the table without throttling the database.

Write a query to randomly sample a row from this table.

Input:

<code>big_table</code> table

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>

Write a query to randomly sample a row from a big table.

Random SQL Sample

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

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Senior/Lead Software EngineerC#, .NET Core, Python, Java, JavaScript, TypeScript, AWS, Kubernetes, Docker.City of London, United KingdomPerm Role: £90,000- £115,000 Harrington Starr has partnered with a Global Financial Technology company, and they are looking to hire a Lead Engineer, with strong commercial experience working with highly scalable and high-performance systems, building APIs and SDKs. This is a great opportunity to join a very well-established, growing global team working to build a resilient and reliable system designing, planning, and implementing new features. Key responsibilities:<ul><li>Contributing to the architectural design of applications.</li><li>Designing, planning and executing new features.</li><li>Line and people management responsibility with the opportunity to grow the team.</li><li>Ensuring consistency across engineering teams, utilising appropriate the appropriate technologies within the applications.</li><li>Providing guidance and mentorship to junior members of the team.</li></ul> Benefits of the role:<ul><li>Flexible hybrid working structure.</li><li>Generous holiday leave.</li><li>Private medical insurance.</li><li>Excellent base salary up to £115,000 based on experience.</li><li>Funded additional training and development and certifications.</li></ul> What skills, experience and qualifications required:<ul><li>Excellent commercial experience with object orientated programming languages.</li><li>Excellent and demonstrable experience building APIs and SDKs.</li><li>Experience working with cloud technology (Azure/AWS).</li><li>Strong technical direction and leadership.</li><li>Strong commercial experience working with highly scalable and high-performance systems.</li><li>Excellent communication skills.</li><li>Full, unrestricted right to work in the UK.</li></ul> This role offers hybrid working, with an office location based in the City of London. You will be joining the team in a lead role, with the opportunity to train and mentor junior Software Developers. This role will suit a Senior/Lead Software Engineer, with expert hands on development experience, having a direct impact from the get-go! For any additional questions, please contact me via LinkedIn or through email - ollie.bluck@harringtonstarr.com. If you feel this role is the right one for you, please apply below!

Senior/Lead Software EngineerC#, Python, Java, APIs, SDKs, Kubernetes, Docker.City of London, United KingdomPerm Role: £90,000 - £115,000 Harrington Starr has partnered with a Global Financial Technology company, and they are looking to hire a Senior/Lead, with experience working with highly scalable and highly-performant systems. This is a great opportunity to join a very well-established, growing global team working to build a resilient and reliable system designing, planning, and implementing new features. Key responsibilities:<ul><li>Leading the design, development and maintenance of their APIs and SDKs across a variety of OOP Languages.</li><li>Ensuring consistency across engineering teams, utilising appropriate the appropriate technologies within the applications.</li><li>Providing technical guidance and mentorship to junior members of the team - with the potential to build out this team further.</li></ul> Benefits of the role:<ul><li>Flexible hybrid working structure.</li><li>Generous holiday leave.</li><li>Private medical insurance.</li><li>Excellent base salary up to £115,000 based on experience.</li><li>Funded additional training and development and certifications.</li></ul> What skills, experience and qualifications required:<ul><li>Excellent commercial experience with C#, Python, Java and TypeScript.</li><li>Experience working with cloud technology (Azure/AWS).</li><li>Strong technical leadership experience.</li><li>Strong commercial experience working with highly scalable and high-performance systems. Excellent communication skills.</li><li>Full, unrestricted right to work in the UK.</li></ul> This role offers hybrid working, with an office location based in the City of London. You will be joining the team in a lead role, with the opportunity to train and mentor junior Software Developers. For any additional questions, please contact me via LinkedIn or through email - ollie.bluck@harringtonstarr.com. If you feel this role is the right one for you, please apply below!

Software EngineerC#, .NET Core, NUnit, Postgres, AWS, Azure, Kubernetes, Docker.City of London, United KingdomPerm Role: £70,000 - £80,000 Harrington Starr has partnered with a Global Financial Technology company, and they are looking to hire a Mid - Senior C#, .Net Software Engineer, with experience working with highly scalable and high-performance systems. This is a great opportunity to join a very well-established, growing global team working to build a resilient and reliable system designing, planning, and implementing new features. Key responsibilities:<ul><li>Hands on contribution to the design of major products and applications.</li><li>Designing, planning and executing new features.</li><li>Ensuring consistency across engineering teams, utilising appropriate the appropriate technologies within the applications.</li></ul> Benefits of the role:<ul><li>Flexible hybrid working structure.</li><li>Generous holiday leave.</li><li>Private medical insurance.</li><li>Excellent base salary up to £80,000 based on experience.</li><li>Funded additional training and development and certifications.</li><li>Excellent bonus structure.</li></ul> What skills, experience and qualifications required:<ul><li>Strong commercial experience with C#, .NET Core.</li><li>Experience working with cloud technology (Azure/AWS).</li><li>Strong commercial experience working with highly scalable and high-performance systems.</li><li>Excellent communication skills.</li><li>Full, unrestricted right to work in the UK.</li></ul> This role offers hybrid working, with an office location based in the City of London. This role will suit a Mid - Senior Software Engineer, with strong C#, .Net experience, having a direct impact from the get-go! For any additional questions, please contact me via LinkedIn or through email - ollie.bluck@harringtonstarr.com. If you feel this role is the right one for you, please apply below!

Software Engineer The company Join a rapidly growing Fintech scale-up as they embark on their next phase of their growth journey. They are quickly becoming known as market leader and are taking the market by storm with their financial technology solutions being used across the globe by instantly recognisable names in finance. They have multiple openings for mid-level software engineers to join their scaling team. What you will get <ul><li>Funded certifications and subscriptions.</li><li>Medical, dental and life insurances for you and family.</li><li>Pension scheme</li><li>Excellent holidays with additional time off for charity days. </li><li>Flexible working with offices in central London. </li><li>Excellent bonus structures paid twice a year. </li><li>£70,000 - £80,000 basic salary.</li></ul> What you will do<ul><li>Engage in the collaborative creation, strategic planning, and successful implementation of cutting-edge features.</li><li>Champion consistency across diverse engineering teams, fostering universal acceptance and proficient utilization of applications and pertinent technologies.</li><li>Drive the development of architectural designs for application systems, playing a pivotal role in shaping their structure and functionality.</li><li>Offer mentorship and support to junior colleagues, actively cultivating a culture of excellence in software engineering practices.</li><li>Advance your professional journey in an environment where your input is valued and your impact is significant.</li></ul> What you will need<ul><li>Excellent C# / .Net experience or willingness to cross train. </li><li>Strong cloud experience.</li><li>Experience working with highly scalable systems or high performance systems.</li><li>Excellent communication skills and desire to learn new technologies.</li><li>Some mentoring experience or experience leading a small team.</li><li>Willingness to commute to a London office occasionally.</li><li>A right to work in the UK indefinitely without sponsorship.</li></ul> Find out moreIf you would like to have a confidential conversation and find out more about this opportunity, or similar roles in Financial technology, then get in touch with Con Lam at Harrington Starr - 07360 532134, click on the apply button below or connect via LinkedIn.

Senior C# EngineerC# Software DeveloperCity of London, On-sitePerm Role: £90,000 - £130,000 Harrington Starr has partnered with an innovative proprietary trading firm working across a variety of markets. This is an excellent opportunity to advance your career and work alongside some of the best engineers in London. What you will get:<ul><li>A chance to work on the latest Microsoft technologies.</li><li>To work in a friendly, non-corporate environment.</li><li>Excellent benefits for you and your family.</li><li>Various perks and in office benefits.</li><li>Up to £130,000 basic salary depending on experience.</li><li>Market leading bonus structure.</li></ul> What you will need:<ul><li>A strong background in back-end C# development.</li><li>Strong commercial experience with .NET Core.</li><li>A strong understanding of SQL Server.</li><li>2:1 or above in Computer Science or related subject.</li><li>Experience working on reporting and data analysis platforms/tools.</li><li>Be willing to work on-site fully from their City of London office.</li><li>Excellent communication skills with fluency in English.</li><li>Right to work in the UK indefinitely without sponsorship.</li></ul> If you would like to book in a confidential phone call to discuss this opportunity in further detail, please apply below or send through a copy of your up-to-date CV via email to ollie.bluck@harringtonstarr.com. You can also reach out to me through LinkedIn, where I will be more than happy to provide further details. Apply below!

Business Analyst£550 - £650 per day6 month rolling contractHybrid working from London. You will be working for a Global Investment Bank as they look to expand their use of Data to further help them in their Finance, Risk and IT Control departments. Gaining an advantage in their highly competitive trading sector. Your responsibilities will vary but will include:<ul><li>Working with senior stakeholders to prioritise, define, collate and document business and technical requirements.</li><li>Work closely with the IT engineering teams to translate specifications into working concepts</li><li>Managing varied data sources to offer analysis in quantitative summaries in the form or Power BI reports</li><li>Provide weekly updates to the senior management</li></ul> Skills required:<ul><li>Trading of Financial Services experience in your recent career (no longer than 3 years ago)</li><li>Strong Business Analysis skills</li><li>Technical skills in querying databases using SQL, Excel and Power BI to produce reports</li><li>Excellent communication and stakeholder engagement skills</li></ul>

Endur Senior Business Analyst – London - Contract £650-7500 per day (Flexible depending on experience) Consultant, Business Analyst, Front office, Middle office, Back office, ETRM, CTRM, Trading delivery systems, Gas, Power, Oil, Agriculture, Commodities, greenfield, Systems analyst Our client is a leading financial institute providing consumers, corporations, governments and institutions with a broad range of financial products and services. They are pioneer in the commodities trading environment. With such great credentials our client is offering an opportunity that cannot be missed to work for a fast growing trading company. They are looking for an Endur Senior Business Analyst to come in on a contract basis and push on the project, who can come with the following skills;<ul><li>Strong Endur system knowledge - including configuration</li><li>Knowledge of trading systems</li><li>Involved in end-2-end project</li><li>Front to back office knowledge - including settlement of physical products</li><li>Good communicative Skills</li><li>Background in energy/commodities (All commodities or metals)</li></ul>Additional experience in accounting or finance will be helpful. We are using SAP for our GL AR AP P2P etc. This opportunity to work with a leader in the European gas and energy trading market. Apply quickly as this is an urgent hire. Click the link provided or email Barry.Ansell@HarringtonStarr.com for a faster response Consultant, Business Analyst, Front office, Middle office, Back office, ETRM, CTRM, Trading delivery systems, Gas, Power, Oil, Agriculture, Commodities, greenfield, Systems analyst

Market Data (Administration & Compliance)DACS / Refinitiv / Bloomberg / Regulatory complianceContract (Inside IR35) We are currently looking for an experienced Market Data Analyst to sit within the administration and compliance team in a growing international bank. The role will require you to:<ul><li>Experience of supporting various Market Data and Trading applications’ user and data licence, agreement, compliance requirements and invoice processing.</li><li>Strong knowledge of different market data providers and experience working on the administration</li><li>You should have a good understanding of DACS</li></ul> This position will require you in the office 5 days per week. Please make sure you are able to do this before applying. archie.odonovan@harringtonstarr.com

Software EngineerOUTSIDE IR35London (1 Day WFH) High-Performance Real-Time Systems Developer Key Responsibilities:<ul><li>Create high-performance, low-latency components for real-time systems, focusing on:</li><li>Real-time market data management</li><li>Trading engine and end-to-end workflow management</li><li>APIs and connectivity for various marketplace and external system integrations</li></ul> Core Competencies:<ul><li>Proficiency in Java, C++, Rust, and TypeScript</li><li>Experience in designing, implementing, and deploying large, complex software projects</li><li>Expertise in systems programming on UNIX variants and Windows</li><li>Strong understanding of sophisticated financial concepts and products</li></ul> Preferred Skills and Abilities:<ul><li>Expertise in Rust development</li><li>Understanding of async Rust and tokio runtime</li><li>Familiarity with Jira and GitHub</li></ul> As mentioned above, this position is 4 days a week in office, (London), and one day working from home. If you can commit to this, then please do apply. We will not be looking for people who are only looking for remote or any less than 4 days in office. If this position is a good fit then please do email me to apply:archie.odonovan@harringtonstarr.com

Harrington Starr Interview Questions

Harrington Starr Interview Guides

Harrington Starr Interview Questions

Harrington Starr Salaries by Position

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