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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

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

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?

Perchwell Salaries by Position

Who We Are Perchwell is the modern data and workflow platform for real estate professionals and consumers. Based on the industry's foundational data, Perchwell builds a modern software suite to empower real estate professionals to do their best work, provide differentiated service to their clients, and grow their businesses. Backed by Lux Capital, Founders Fund, and some of the country's leading Multiple Listing Services (MLSs), Perchwell builds next generation workflow software/data products for the multi-trillion dollar residential real estate industry. Perchwell is the first new entrant to come to market in decades and is currently scaling its best-in-class platform. What We're Looking For: We are looking for an experienced full-stack or backend engineer to take part in all stages of the product development and deployment lifecycle. As part of our small team of developers, you'll collaborate with everyone on building out the team, process, & tech stack as we work on growing both our team, business and technology. Projects We've Tackled in the Past: <ul><li>Developed workflow solutions from the ground up that allow agents to create and edit property listings for some of the most valuable properties across multiple real estate markets.</li><li>Developed an interface to allow users to export custom reports for their clients, allowing them to choose what information to include and how to display it.</li><li>Engineered an advanced search and filter system allowing users to find apartments and analyze the most accurate real-estate dataset in New York.</li><li>Blazing fast real time analytics on the property market driven by Elastic Search</li></ul> What You'll Work On: <ul><li>Develop new client-facing features and interfaces</li><li>Drive large, complex projects autonomously, from technical design to launch</li><li>Determine plans-of-attack on large projects</li><li>Tackle complex architecture challenges, apply architectural standards and start using them on new projects</li><li>Mature our existing tech platform to prepare it to scale with our future growth plans</li><li>Help us define a healthy and effective development culture that balances the need to move quickly with planning for the future.</li><li>Be an example for thorough, meaningful code reviews</li><li>Take ownership over QA and release cycles of your work as part of a you-build-it-you-run-it practice.</li></ul> Required for this Role: <ul><li>BS or MS in Computer Science, related technical field, or equivalent experience</li><li>6+ years of experience collaborating on software development projects</li><li>2+ years experience with Ruby on Rails (our current technology)</li><li>Experience with front end development frameworks with preference for React and Backbone</li><li>Past experience building complex software systems that have successfully been delivered to customers</li><li>Appreciation for (and the ability to create) simple and beautiful UI</li><li>Question assumptions, experiment with new technologies, and find the development of a reliable and maintainable system just as exciting as we do</li></ul> In this role, you'll work out of our New York City HQ in Soho Manhattan at least 3 days/week. Bonus Points for Any of the Following: <ul><li>Expertise with the following technologies: <ul><li>Elasticsearch & PostgreSQL</li><li>Rails fundamentals: ActiveRecord/ActiveQuery, ActionController, ActionMailer</li><li>Delayed job or other message queue implementations</li><li>CoffeeScript</li><li>AWS services including: EC2, RDS, CloudFront, ECR, S3, and Route53, or PostgreSQL</li></ul></li><li>Implementing RESTful APIs and, in particular, OData-compliant services</li><li>Working with omnichannel communication APIs (incl. email, SMS, push notifications, etc.)</li></ul>Salary Range: The compensation for this position is $165K-$195K base salary + equity + benefits To provide greater transparency to candidates, we share base salary ranges for all US-based job postings regardless of state. Our ranges are based on function and level benchmarked against similar stage growth companies. Final offer amounts are determined by multiple factors including skills, job-related knowledge and depth of work experience. Benefits: <ul><li>Unlimited PTO, plus 10 paid company holidays</li><li>401K with a company match</li><li>Medical, dental, and vision plans</li><li>HSA and FSA options</li><li>Commuter benefits</li><li>Parental leave</li><li>Company-wide onsite or offsite each year</li><li>Beautiful office in Soho, Manhattan with a stocked kitchen, catered breakfast and lunch once per week, happy hours and meet-ups</li></ul> Note: At this time, we are only considering candidates who are authorized to work in the U.S.

Who We Are Perchwell is the modern data and workflow platform for real estate professionals and consumers. Based on the industry's foundational data, Perchwell builds a modern software suite to empower real estate professionals to do their best work, provide differentiated service to their clients, and grow their businesses. Backed by Lux Capital, Founders Fund, and some of the country's leading Multiple Listing Services (MLSs), Perchwell builds next generation workflow software/data products for the multi-trillion dollar residential real estate industry. Perchwell is the first new entrant to come to market in decades and is currently scaling its best-in-class platform. What We're Looking For: We are looking for an experienced backend engineer, focused on Ruby on Rails, to take part in all stages of the product development and deployment lifecycle. As part of our small team of developers, you'll collaborate with everyone on building out the team, process, & tech stack as we work on growing both our team, business and technology. You will have the opportunity to partner across functions to design, build and implement new systems/features that better improve our products to serve our customers. Our engineering team is broken into 6 different pods. In this role, you will be a part of our Disco team currently made up of 4 members. We believe that in an ever-changing, innovative environment, we do our best work when we are working as a team in-person. In this role, you'll work out of our New York City HQ in Soho Manhattan at least 3 days/week. Projects We've Tackled in the Past: <ul><li>Developed workflow solutions from the ground up that allow agents to create and edit property listings for some of the most valuable properties across multiple real estate markets.</li><li>Developed an interface to allow users to export custom reports for their clients, allowing them to choose what information to include and how to display it.</li><li>Engineered an advanced search and filter system allowing users to find apartments and analyze the most accurate real-estate dataset in New York.</li><li>Blazing fast real time analytics on the property market driven by ElasticSearch</li></ul>What You'll Work On: <ul><li>Develop new client-facing features</li><li>Drive large, complex projects autonomously, from technical design to launch</li><li>Determine plans-of-attack on large projects</li><li>Tackle complex architecture challenges, apply architectural standards and start using them on new projects</li><li>Mature our existing tech platform to prepare it to scale with our future growth plans</li><li>Help us define a healthy and effective development culture that balances the need to move quickly with planning for the future.</li><li>Be an example for thorough, meaningful code reviews</li><li>Take ownership over QA and release cycles of your work as part of a you-build-it-you-run-it practice.</li></ul>Required for this Role: <ul><li>BS or MS in Computer Science, related technical field, or equivalent experience</li><li>6+ years of experience collaborating on software development projects</li><li>4+ years experience with Ruby on Rails (our current technology)</li><li>Proven experience in designing efficient data models and diagnosing performance bottlenecks in PostgreSQL, including query optimization, index tuning, and analyzing execution plans</li><li>Past experience building complex software systems that have successfully been delivered to customers</li><li>Question assumptions, experiment with new technologies, and find the development of a reliable and maintainable system just as exciting as we do</li><li>Strong communicator who can explain complex topics cross-functionally</li></ul>Bonus Points for Any of the Following: <ul><li>Expertise with the following technologies: <ul><li>Elasticsearch & PostgreSQL</li><li>Rails fundamentals: ActiveRecord/ActiveQuery, ActionController, ActionMailer</li><li>Delayed job or other message queue implementations</li><li>CoffeeScript</li><li>AWS services including: EC2, RDS, CloudFront, ECR, S3, and Route53, or PostgreSQL</li></ul></li><li>Implementing RESTful APIs and, in particular, OData-compliant services</li><li>Working with omnichannel communication APIs (incl. email, SMS, push notifications, etc.)</li><li>Experience working at a high-growth startup, real estate/tech company or real estate</li><li>Appreciation for (and the ability to create) simple and beautiful UI</li></ul> Note: At this time, we are only considering candidates who are authorized to work in the U.S.

Perchwell Interview Questions

Perchwell Interview Guides

Perchwell Interview Questions

Perchwell Salaries by Position

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