Data Sciences Challenges
Explore data science challenges on Ewance to build skills employers expect from analysts and ML engineers. Work through challenges on data cleaning, exploratory analysis, modeling, and storytelling with data.
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- DesignIntermediateNew
Design and Run a Platform-as-Product Quarterly Review
Using the platform product catalog (platform-product-catalog) and the Head of Platform's mandate (head-of-platform-brief), design a complete, repeatable quarterly review for the…
- Platform Engineering
- Platform As Product
- Facilitation
Open coursework - CodeIntermediateNew
Add Differential Privacy to a Mental-Health App's Analytics Dashboard
Wrap the analytics module in `analytics_module.py` (provided) with a differential-privacy layer built on OpenDP. Implement epsilon-delta accounting: add Laplace noise to counts …
- Differential Privacy
- Privacy Budget
- Python Programming
Open coursework - CodeSeniorNew
Assess Secure Cross-Bank Fraud Computation for a Four-Bank Consortium
Using the de-identified situation in the consortium case file and the two synthetic per-bank datasets (the bank suspicious-account lists and the merchant fraud-marker tallies), …
- Secure Computation
- Mpc
- Cryptography
Open coursework - CodeIntermediateNew
Implement Federated Learning for a Government Statistics Office
Use Flower as the FL framework. Simulate 8 municipalities each with a partition of a synthetic wage dataset (provided, 1M rows, EU-Labour-Force-Survey schema). Train a gradient-…
- Federated Learning
- Differential Privacy
- Python Programming
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- AnalysisBeginnerNew
GDPR Article 25 Privacy-By-Design Review for a HealthTech API
Review the API specification (OpenAPI 3, provided, 42 endpoints). For each endpoint: identify data categories handled (special-category health data, identifiers, traffic data), …
- GDPR
- Privacy By Design
- API Design
Privacy-Enhancing Technologies - StrategyIntermediateNew
Design a Bundled Pricing Business Case for an Industrial IoT Vendor
Using the company facts in the company case file, the historical deal records in the deal-history dataset, and the required sections listed in the board business case template, …
- Business Case
- Financial Modeling
- Pricing Strategy
Open coursework - StrategyBeginnerNew
Lead a Coordinated AI Feature Launch for an HR Software Startup
Using the company background brief and the draft feature specification provided, design a six-week launch plan covering four parallel workstreams: product readiness (acceptance …
- Product Launch
- Cross Functional Coordination
- Go To Market
Open coursework - CodeIntermediateNew
Build a CodeQL Query Pack to Catch Logging of Personal Data
Using the provided personal-data source and logging-sink specification, write CodeQL data-flow queries for Java and Python that detect personal data travelling from a source (re…
- Static Analysis
- Codeql
- Data Flow Analysis
Open coursework - Browse challenges
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Pricing Strategist
Set the price that captures value without leaving sales on the table. Demand modelling, willingness-to-pay research, and the disciplined experimentation that turns pricing into a competitive advantage.
- CodeSeniorNew
Detect Use-After-Free with Pointer Analysis in a C++ Codebase
Build the codebase with compilation database (compile_commands.json). Write a custom Clang static-analyzer checker (or extend an existing one) that flags resource-handle uses af…
- Pointer Analysis
- Static Analysis
- Use After Free
Program Analysis - CodeIntermediateNew
Find the Dead Code Hiding in a Python Monorepo
Build a dataflow- and call-graph-based dead-code detector in Python (using libcst, or the standard ast module together with jedi) and prove it on the materials provided. Run it …
- Dataflow Analysis
- Ast
- Call Graph
Open coursework - DesignSeniorNew
Design a Semantic Configuration Validator Using Abstract Interpretation
Using the configuration schema reference, the three incident post-mortems, and the 200-configuration validation set provided, design an abstract domain that captures relations b…
- Abstract Interpretation
- Static Analysis
- Rust Programming
Open coursework - CodeBeginnerNew
Refactor a Legacy Reporting Script for a Renewable-Energy Startup
Read the existing script and identify 5-7 distinct responsibilities tangled together. Refactor into 3 layers: data loaders (CSV, REST API), transformers (pure functions over row…
- Abstraction
- Higher Order Functions
- Refactoring
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- CodeBeginnerNew
Build a Safe Expression Evaluator for a Math-Learning App
Working only from the materials provided, build a self-contained expression evaluator in Python (TypeScript is acceptable if you mirror the same structure) that never calls eval…
- Recursion
- Higher Order Functions
- Parsing
Open coursework - CodeBeginnerNew
Build a Functional Image-Filter Pipeline for a Photography SaaS
Design a Filter as a function from (pixel matrix → pixel matrix). Build a compose helper that takes a list of filters and returns a single composed filter (function composition)…
- Higher Order Functions
- Function Composition
- Abstraction
Programming Abstractions - CodeIntermediateNew
Build a Shareable Immutable List for a Real-Time Document Editor
Using the provided API specification (persistent-list-spec) and the starter module (immutable-list-starter), implement a persistent immutable list supporting get, set, append, p…
- Data Abstraction
- Recursion
- Persistent Data Structures
Open coursework - DesignIntermediateNew
Design an Invoice-Rules Mini-Language for Non-Technical Users
Design a rule mini-language whose grammar (written in Backus-Naur Form, the standard notation for describing grammars) covers boolean logic (and / or / not), comparison operator…
- Abstraction
- Recursion
- Domain Specific Language
Open coursework - CodeIntermediateNew
Bloom Filter Cache to Cut Origin Load at a CDN Edge
Given a target false-positive rate of 1 percent at 200 million keys per shard, compute the optimal bit-array size (m) and hash-function count (k) using the canonical formulas. I…
- Bloom Filters
- Probabilistic Data Structures
- Hash Functions
Randomized Algorithms - CodeIntermediateNew
MinHash Similarity Sketch for a Job-Board Deduplication Pipeline
Implement a MinHash signature generator (128 permutations) over shingled job-posting text (5-gram word shingles). Build an LSH banding index (16 bands of 8 hashes each) tuned fo…
- Minhash
- Locality Sensitive Hashing
- Probabilistic Data Structures
Randomized Algorithms - CodeSeniorNew
HyperLogLog Cardinality for Real-Time Ad-Auction Analytics
Implement HyperLogLog with precision parameter p in {12, 14, 16} (4KB, 16KB, 64KB sketches) and benchmark relative error on a replayed 3-hour production trace (around 13 billion…
- Hyperloglog
- Probabilistic Data Structures
- Streaming Systems
Randomized Algorithms - AnalysisIntermediateNew
Randomized Load Balancer with the Power of Two Choices
Simulate four placement policies on a 24-hour anonymized connection-establishment trace (around 4.1 billion events): (1) random-1, (2) round-robin, (3) P2C with instantaneous lo…
- Power Of Two Choices
- Load Balancing
- Randomized Algorithms
Randomized Algorithms - CodeIntermediateNew
Reservoir Sampling for a Privacy-Preserving Telemetry Pipeline
Implement Vitter's Algorithm R (and the faster Algorithm L for bonus credit) producing a 90M-event uniform sample per day from a stream of 18B. Add per-key stratification (so lo…
- Reservoir Sampling
- Randomized Algorithms
- Streaming Systems
Randomized Algorithms - CodeBeginnerNew
Characterization Tests for an Untested Pricing Engine
Drive the pricing engine with around 800 representative input vectors generated from anonymized production quotes (provided). For each vector, capture the current output as the …
- Characterization Tests
- Approval Testing
- Legacy Code
Refactoring and Code Smell Detection - DesignBeginnerNew
Validate a Signed Construction-Permits Requirements Document
Using the requirements excerpt (req-doc-excerpt), the anonymized permits dataset (permits-dataset), and the intake notes from the first case-handler session (intake-notes), conv…
- Requirements Validation
- Executable Scenarios
- Gherkin
Open coursework - CodeIntermediateNew
Multi-Tenant Schema Migration for a Series-B HR SaaS
Design a 4-phase migration: (1) add new columns + tables, dual-write on every workflow mutation, (2) backfill 3.4 TB in chunks of around 50k rows per minute with throttling and …
- Multi Tenant Architecture
- Schema Migration
- Dual Write
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