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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?

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

Idexcel Salaries by Position

Data Scientist 5 to 10 YearsJob DescriptionRequired SkillsMinimum Qualifications1. Must-Have: Python programming, ML, NLP, or Computer Vision. (AWS or Azure or Google cloud)2. Minimum of 2 to 8 years of relevant experience in implementing and deploying Machine Learning solutions (using various models, such as Linear/Logistic Regression, Support Vector Machines, (Deep) Neural Networks, Hidden Markov Models, Conditional Random Fields, Topic Modeling, Game Theory, Mechanism Design, etc.)3. Extensive experience in handling Time-series data4. Extensive background in statistical analysis and modeling (distributions, hypothesis testing, probability theory, etc.)5. Experience in working on anomaly detection6. Experience in handling structured and unstructured data.7. Strong hands-on experience with statistical packages and ML libraries (e.g. Python scikit learn, Spark MLlib, etc.)8. Experience in developing and debugging in one or more of the languages Python

Job Title: Sr Data ScientistLocation: Vienna, VADuration: Long Term Top 3 Required Skills:• Python• SQL• Data warehouse usage Top 3 Desired Skills:• Machine Learning• Data Science• Statistics Desired : Master's Degree in Data Science, Statistics, Mathematics, Computer Science, or Engineering Qualifications:2-3 years of experience in exploratory data analysis ,StatisticsProgramming, data modeling, simulation, and mathematicsSQL, R, Python, Hadoop, SAS, SPSS, Scala, AWSModel lifecycle executionTechnical writingData storytelling and technical presentation skillsResearch SkillsInterpersonal SkillsModel DevelopmentCommunicationCritical ThinkingCollaborate and Build RelationshipsInitiative with sound judgementTechnical (Big Data Analysis, Coding, Project Management, Technical Writing, etc.)Problem Solving (Responds as problems and issues are identified)

Job Title: Mid-Level Pega DeveloperLocation: Vienna, VA/Pensacola, FL/ San Diego, CADuration: Long Term Hybrid Days in-office requirement: 2x a week or 8x a month Skills (required – All Advanced Level):Hands-on experience creating automated data pipelines using modern technology stacks for batch ETL, and for data processing to load advanced analytics data repositoriesHands-on experience with data warehousing, PostgreSQL, Cassandra, Cloud technologies (AWS, ADLS).Experience with SQL, Procedures and Packages Description: Develop technical solutions for data acquisition, data integration, and data sharing in translating our business vision and strategies into effective IT and business capabilities through the design, implementation, and integration of IT systems utilizing legacy systems, Microsoft Azure and Pega Cloud (AWS). The Data Engineer will be responsible for guiding the design, development, of our Data with a specific focus on Azure Data Factory, ADLS pipelines, AWS Glue, AWS pipelines to support Pega Marketing systems capabilities and on integrating data from Teradata, other external source, and applications into high performing operational Hubs, Data Lake and Microsoft SQL Server. Recognized as an expert with a specialized depth and/or breadth of expertise in discipline. Solves highly complex problems; takes a broad perspective to identify solutions. Leads functional teams or projects. Works independently. Responsibilities:Load Customer Data into Pega CDH on Pega Cloud, monitor data quality and implement related controls.Migrate existing ETL for the Pega marketing PaaS solution to a Pega managed service in the cloud, SaaS solution.Design and implement data frameworks and pipelines to process data from on-premises and cloud data sources to feed into the Pega AWS (PostgreSQL), Azure Data storages, monitor data quality and implement related controls.Technical leadership and knowledge to provide technical guidance and educate team members and coworkers on development and operations.Evaluate existing designs, improve methods, and implement optimizations.Document best practices for data models, data loads, query performance and enforce with team members.Implement integration plans and interface with testing teams to incorporate plans into the integration testing process.Perform data archival.Analyze and validate data sharing requirements within and outside data partners.Work directly with business leadership to understand data requirements; propose and develop solutions that enable effective decision-making and drives business objectives. Qualifications (Required):Bachelor’s degree in Information Systems, Computer Science, Engineering, or related field, or the equivalent combination of education, training, and experience All Advanced level:Very good understanding of SQL, Procedures and PackagesHands-on experience creating automated data pipelines using modern technology stacks for batch ETL, and for data processing to load advanced analytics data repositories.Hands-on experience with data warehousing, PostgreSQL, Cassandra, Cloud technologies (AWS, ADLS).

Job Title: Technical Business AnalystLocation: Vienna, VA/Hybrid modelDuration: Long Term Hybrid Days in-office requirement: 2x a week or 8x a month Basic Purpose:The Technical Analyst position supports Client's Digital team in developing industry leading web and mobile solutions to meet our Members’ evolving financial needs and provide internal Member Service Representatives (MSRs) with capabilities to support those needs.The role involves collaboration with business analysts, solution architects, developers, and testers to assess needs and define the technical system requirements for solutions.The team’s portfolio ranges from Member and MSR facing capabilities to supporting infrastructure and services. Top 3 Required Skills:Excellent communication and collaboration skillsPutting together API services request and response elements and/or testing of the same, using tools such as Postman or Soap UI or something similarSetting up and running SQL scripts for database querying and updating Top 3 Desired Skills:Worked in an agile environment and has an agile mindsetKnowledge of and/or use of Azure Dev OpsWriting clear and concise documentation Qualifications/Experience:Ability to write SQL queriesProblem solving skill – Works well under pressure and challenges, team-player, good listener, analytical, creative, approachable, etc.Excellent verbal and written communication skills with the ability to partner with various levels of leadership within the organizationConducting complex technical analysis across multiple productsWork in Agile methodologyWriting requirements for a systemWriting mobile and/or web application requirements is a plusWriting mobile service and/or web service requirements is a plusProficiency with API access tools such as Postman and SoapUI is a plus Job Description:Collaborates with product ownership to translate business need into the technical system requirements of the productLeverages available documentation and exercises test versions of applications and APIs to understand existing functionality to inform replatforming and enhancement opportunitiesInvestigates enterprise and vendor APIs to determine whether necessary data is available to support intended system capabilitiesMaps data between interfacing systemsAssists lead analysts in developing and prioritizing features and epics to ensure work focuses on requirements with maximum value and are aligned with product delivery strategyParticipates in project planning, sprint and release planning, daily stand-up meetings (scrums), demos/reviews, retrospectives, backlog refinement meetings, and other Scrum-related meetings.Performs application and services tests.Responsible for creating system requirement documentation for applications and services, including interface specifications.Provides demos to internal project team, as well as to business stakeholders.Works closely with Business, Quality Assurance team and developers on projects and to address production issues.Demonstrates ability to excel in a fast-paced environment with aggressive timelines that require managing multiple priorities concurrentlyUtilizes system documentation, database information, application logs and scenario testing to determine root cause of system issues. Have in-depth understanding or working knowledge of the following:Services-Oriented Architecture / MicroservicesMulti-tier applications (presentation tier/services-processing tier/data management tier)Enterprise and vendor API integrationManaging system behavior through configurable variablesError handlingXML and JSON data structures

Job Title: Senior Data ScientistLocation: Raleigh, NC/Hybrid modelDuration: Long term Description:Identifies business trends and problems through complex big data analysis. Interprets results from multiple sources using a variety of techniques, ranging from simple data aggregation via statistical analysis to complex data mining independently. Designs, develops and implements the most valuable business solutions for the organization.Prepares big data, implements data models and develops database to support the business solutions. List of Tasks to be Performed:Task #1: Data Analysis and Visualization DevelopmentDeliverables will be tailored to each project and may include:Rapid analysis scripts, Visualization prototypes /models, Interactive dashboards, Visioning session materials, Analysis reports and presentations,Project plans and documentationThe deliverable shall meet the following acceptance criteria in addition to compliance with the technical approach outlined below:Analysis techniques are appropriate for the given need and available dataProject timelines are met within a reasonable variance due to uncertainty of the individual projectProject documentation is accurate to the analysis findings and free of grammatical errorsProducts meet the Business Units needs and are usable by the Business Unit with minimal training Task #2:Modeling and OptimizationDeliverables are project-dependent and may include: Mathematical optimization models, Source code and/or scripting, Translational documentation for use in analytical and visualization product developmentProposal presentationsProject result documentation and presentationsThe deliverable must meet the following acceptance criteria in addition to compliance with the technical approach outlined below:Model parameters and functions are appropriate for the given need and available dataProject timelines are met within a reasonable variance due to uncertainty of the individual projectProject documentation is accurate to the analysis findings and free of grammatical errorsProducts meet the Business Units needs and are usable by the Business Unit with minimal trainingRequired Certification/Experience Level/Education that displays the following:-Some academic criteria for data science - Ex. Data science, statistics, or experimental psych.Skilled in SQL, Python or R, preferably both. Education Requirements:A minimum of thirteen (13) to twenty (20) years relevant experienceA degree from an accredited College/University in the applicable field of services is preferred. four additional years of relevant experience in lieu of a college degree is required.If the individual's degree is not in the applicable field, then four additional years of related experience is required. Additional Provisions:Pass both a client mandated clearance process to include drug screening, criminal history check and credit check.Once candidates resume is approved and interview passed, the agency is responsible for providing drug screening.Failure to submit the drug screening results will delay the security clearance process.If a candidate is given an interim clearance, continuation of employment is then based on the candidate receiving a sensitive clearance.All candidates must be a US Citizen or have permanent residence status (Green Card) or H1B.Candidate must have lived in the United States for the past 5 yearsCannot have more than 6 months travel outside the United States within the last five years. Military Service excluded. (Exception does not include military family members.)All overtime must be pre-approved in writing by the client manager or his/her designated representativeAgency will not be reimbursed for overtime charges without previous written authorization. Authorized overtime will be reimbursed at straight time.The enforced dress code is business casual, i.e., collared shirt with slacks for men, no skirts above the knee for women

Job Title: Mid - Senior Level Software Development Engineer in TestLocation: Vienna, VA/ Pensacola, FL/ San Diego, CADuration: Long Term Hybrid Days in-office requirement: 2x a week or 8x a month Top Skills:Full Stack SDET (Front-End and Back-End Automation Test Exp Required) Top 3 Required Skills:Hands-on development/coding (Java)Hand on experience with UI+API+DB automation testingHands experience on a wide variety of testing techniques and types and STLC process Top 3 Desired Skills:Hands-on development/coding (Java)Hand on experience with UI+API+DB automation testingHands experience on a wide variety of testing techniques and types and STLC process Job Description: Mid -Senior Level Software Development Engineer in Test (SDET)Basic Purpose:The Digital Delivery team develops innovative member and team member experiences that leverage the latest technologies in open source and the Azure cloud. Digital Delivery team is responsible for engineering modern web applications to implement a complete UI and micro services for multi device, multi-platform mobile and desktop web applications. As a member of this team your role will be a Software Development Engineer in Test (SDET) working in a Scrum environment, you will test software applications and features using test suites and scripts, perform anomaly reporting, software analysis, develop automated software test packages using various technologies, perform functional and performance testing.Additionally, SDET is responsible for providing support for one or more existing software applications. This includes application issue-analysis/resolution, configuration, managing security/permissions, and providing assistance to users. Responsibilities:• Work with engineers to troubleshoot and remediate automation issues in testing and deploying environments• Work alongside developers as well as the business stakeholders and strive to automate the acceptance criteria• Understand, and implement agile development methodologies while working with teams using the Sprint/Scrum methodology of agile• Understand project documents, customer demands, and product objectives to create and execute test cases• Test complex API, web and mobile based applications that reference database back-end systems• Support non-functional requirements such as, performance testing• Set up, maintain, and perform test automation frameworks on multiple application platforms, such as Mobile, Desktop, and Web, and building test scenarios and acceptance tests• Participate in all agile ceremonies (standups, planning, backlog refinement, reviews, etc.) ensuring QA and testing is continuously represented and effectively incorporated into all aspects of the project• Own end-to-end test strategy, analyze requirements, build test plan, design test cases and implement test automation for applications of moderate to high complexity• Manage the final quality on production release• Develop, execute, and maintain automation test scripts to meet software release deliverables, project testing requirements and other quality considerations• Develop smoke, functional, regression, and integration test suites for UI, API Services, and databases• Develop and execute manual test cases to detect issues that cannot be detected through automated means (when needed)• Design customer centric automation test processes for all existing and new product development• Apply a strong understanding of software testing/delivery to build and maintain automated test harnesses and test suites using scripting languages and industry tools• Ability to advocate for Improvements in automation engineering efforts to the executive management team Qualifications: • At least 5 years overall SDET and/or development hands on experience.• At least 2 years of mobile apps test automation experience in Android and/or iOS, Web, API• At least 4 years of professional experience in software test automation, including creation and deployment of frameworks and design and maintenance of test automation• At least 2 years of API Automation Testing.• Experience with agile development methodology• Experience with Cl/CD pipelines using tools such as GitHub, Jenkins, JUnit, Selenium, Cucumber, etc.• Experience with Test Driven Development (TDD), BDD Behavior Driven Development, and Agile (XP)• Experience with Test processes, open-source test frameworks, test design strategies, writing test cases, and automating tests in Java with frameworks like JUnit/TestNG, Selenium, JMeter and Appium• Experience working with a ticketing system such as Service Now or Jira• Hands on experience with any cloud technology platforms, preferably Microsoft Azure.• Must have hands on experience in Selenium Scripting, and SQL querying• Must have hands on experience utilizing cloud hosted testing platforms such as Perfecto.• Proficient in debugging issues.• Proficient in Java• Proficient in writing functional automation (UI/API)• Solid foundation in data structures, algorithms, design patterns and strong analytical and problem- solving skills.• Working knowledge of Pull requests, code reviews, etc. Hours: Monday - Friday, 8:00 AM – 4:30 PM

Idexcel Interview Questions

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Idexcel Interview Questions

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