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<p>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.</p>

<p>Write a query to randomly sample a row from this table.</p>

<p><strong>Input:</strong></p>

<p><code>big_table</code> table</p>

<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

<p>You are testing hundreds of hypotheses with many <em>t</em>-tests. What considerations should be made?</p>


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

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?

<p>Let’s say you work for a social media company that has just done a launch in a new city. Looking at weekly metrics, you see a slow decrease in the average number of comments per user from January to March in this city.</p>

<p>The company has been consistently growing new users in the city from January to March.</p>

<p>What are some reasons why the average number of comments per user would be decreasing and what metrics would you look into?</p>


<p>What metric could be used to measure if active users are still engaging on the platform despite an overall decrease in the average number of comments per user?</p>

What metric could be used to measure if active users are still engaging on the platform despite an overall decrease in the average number of comments per user?

Decreasing Comments

How would you investigate a decline in the average number of comments per user?

Celestar Salaries by Position

<p>Celestar Corporation is seeking multiple Data Engineers - Mid Level who will perform duties at Redstone Arsenal, AL . If interested and qualified, we welcome you to apply for this challenging opportunity. CLEARANCE REQUIREMENT : Active Top-Secret Level Clearance with SCI Access. Clearance, Access and Investigation must appear in JPAS and be within scope (5 - Years). ANTICIPATED AWARD DATE: November/December 2023 ANTICIPATED START DATE: January/February 2024 PERIOD OF PERFORMANCE: 1 Base Year 4 Option Years LOCATION: Redstone Arsenal, AL About Us : Celestar, a Veteran Owned Company is Very Competitive with Salaries and Benefits. As an example, we offer Company Paid Benefits that include Employee and Family Dental Insurance, Employ Health Insurance, Life Insurance and Disability Insurance as well. We also offer a 401K retirement company match, paid Holidays and Personal Time off. BACKGROUND : The Artificial Intelligence (AI)/Machine Learning (ML) investment is a combined O&M and RDT&E funded effort focusing on improving analytic enabling abilities and data-processing intelligence requirements. This is a scalable approach to increase analytic capabilities across the DIE to meet the growing data processing and analytic enabling requirements. The focus of this effort is to provide the Defense Intelligence Agency (DIA) and Missile and Space Intelligence Command (MSIC), with a robust support contract to aid in the development, refinement, and integration of technology advancement services in the areas of and around AI & ML. OBJECTIVES : Provide a full range of data engineering and data science capabilities that enable advanced analytic capabilities that support the Directorate of Analysis and the entire MSIC mission set. In pursuit of its mission to support DI/MSIC, MSIC-4's enabling of analysis and production must comply with the requirements set forth in Intelligence Community Directive (ICD) 203, "Analytic Standards." MSIC-4 accomplishes its mission using data engineering and computer science teams with cross-functional expertise in topics including data science, data engineering, computer science and application prototype development. MSIC-4 is at the forefront of developing advanced capabilities and tools that comply with tradecraft requirements, enhance the rigor of intelligence production, and automated processes and capabilities. RESPONSIBILITIES Design, implement, and operate data management systems for intelligence needs. Design how data will be stored, accessed, used, integrated, and managed by different data regimes and digital systems. Work with data users to determine, create, and populate optimal data architectures, structures, and systems. Plans, designs, and optimizes data throughput and query performance. Participates in the selection of backend database technologies (e.g. SQL, NoSQL, HPC, etc.), their configuration and utilization, and the optimization of the full data pipeline infrastructure to support the actual content, volume, ETL, and periodicity of data to support the intended kinds of queries and analysis to match expected responsiveness. Maintain and extend existing data centralization and automation software. Collaborate with MSIC personnel and shares leading practices and lessons learned in formal training events. REQUIREMENTS Possess proven work experience or formal training as a Data Engineer, Machine Learning Engineer, or similar role. Provides expertise in Python software development: (1) uses Python to read, create, and modify relational and graph databases, (2) uses Python to provide REST API services for databases, (2) uses GIT for software version control, (3) familiarity with Agile development methodologies, (4) Familiarity full software development life cycle (SDLC), (5) Complies with industry standards and best practices. Maintains and extends existing automation software: (1) provides expertise in Apache Airflow, (2) uses Apache Airflow to design and implement data pipelines for extract, transform, and load operations, (3) uses Apache Airflow to design and implement pipelines for task automation, (4) uses Python and Apache Airflow to develop production machine learning pipelines from existing prototype models, (5) works with data scientist and algorithm developers to design and implement software applications pertaining to data and ML pipelines. Provides expertise in Linux OS and Docker: (1) uses Linux OS as primary development environment, (2) uses Docker to containerize existing software applications. Maintains and extends existing data infrastructure: (1) provides expertise in databases and database design, including both SQL, NoSQL, and ORMs, (2) provides expertise in developing data models for various data modalities. Maintains and extends software documentation according to 'best practices': create technical documentation, flow charts, and specifications for reference, reporting, and security. Exceptional oral and written communication skills Valid US Passport EDUCATION & EXPERIENCE : Subject Matter Expert : Master's Degree and twenty ( 20) years of experience with at least a portion of the experience within the last 2 years. Senior : Master's Degree and twelve ( 12) years of experience or Bachelor's Degree and an additional five (5) years of related experience for a total of seventeen (17) years in lieu of a Master's Degree with at least a portion of the experience within the last 2 years. Mid Level : Bachelor's Degree in a related field; Minimum eight (8) years of experience conducting analysis relevant to the position, with at least a portion of the experience within the last two (2) years. IMPORTANT NOTE : This is a Best Athlete Selection Process Please ensure that the required and/or desired experience is reflected on your resume to receive fair and competitive consideration. Come onboard with a company that Values its Employees Celestar is an Equal Opportunity/Affirmative Action Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, age, protected veteran status, disability status, gender identity or national origin.</p>

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