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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

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.

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

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

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?

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?

Colsa Salaries by Position

General Summary: Data Analytics with Power BI Support our Army customer as a Data Analyst, by recognizing business requirements in the context of BI and creating data models to transform raw data into relevant insights for senior leadership. Identify trends and issues with an emphasis on sound judgment, and initiative. Work closely with a high-performing, fast-paced team to develop products for decision-makers. Responsibilities + Integrate data from multiple sources to produce requested or required data elements + Develop and maintain complex data models for business data analysis and reporting purposes + Using Power BI, create dashboards and interactive visual reports + Define key performance indicators (KPIs) with specific objectives and track them regularly + Analyze data and display it in reports to aid decision-making + Convert business needs into technical specifications and establish a timetable for job completion + Create, test, and deploy Power BI scripts, as well as execute efficient deep analysis + Use Power BI to run DAX queries and functions + Create charts and data documentation with explanations of algorithms, parameters, models, and relationships + Use SQL queries as applicable to get the best results for data analysis and visualization + Develop briefings for a better understanding of the data, by using filters and visualizations + Analyze current ETL procedures to define and create new systems At COLSA, people are our most valuable resource and centered at our core value. We invite you to unite your talents with opportunity and be a part of our Family of Professionals! Learn about our employee-centric culture and benefits here (https://www.colsa.com/culture_benefits/) . Required SkillsRequired Experience + Bachelor's degree in computer science, data science, engineering, math, statistics, operations research, business, or related field or equivalent experience + Minimum of 3 years of related experience + Active Secret security clearance + Must be proficient in Microsoft Outlook, Excel, Word, and PowerPoint + Background with BI tools and systems such as Power BI, Tableau, and SAP + Prior experience in data-related tasks + Understanding of the Microsoft BI Stack + Mastery in data analytics + Should be proficient in software development + Be familiar with MS SQL Server BI Stack tools and technologies, such as SSRS and TSQL, Power Query, MDX, PowerBI, and DAX + Analytical thinking for converting data into relevant reports and graphics + Capable of enabling row-level data security + Knowledge of Power BI application security layer models + Ability to run DAX queries on Power BI desktop + Proficient in doing advanced-level computations on the data set + Excellent communication skills are required to communicate needs with client and internal teams successfully Preferred Skills + MS in Applied Data Science + Familiarity with APAS, Vantage, and Advana + CompTIA Data+ + Google Data Analytics Professional Certificate or Microsoft Certified: Power BI Data Analyst Associate Applicant selected will be subject to a government security investigation and must meet eligibility requirements for access to classified information. COLSA Corporation is an Equal Opportunity Employer, Minorities/Females/Veterans/Disabled. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, or national origin.

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