
This course contains the use of artificial intelligence. Data Scientist Job: Day-to-Day Work Inside a Company is a practical course on how a data scientist works inside a real company. You will learn how to frame a business question with product partners, explore data with SQL and Python, design an A/B test, build a forecast, train and evaluate a predictive model, separate prediction from causal claims, and present evidence that supports a product decision.
The course follows Adam Vail, Data Scientist, a new joiner on the Decision Science and Experimentation team at Walnut Keystone Corporation, a fictional global online furniture retailer. You see one data science project from start to end: a lateness-risk model defines which delivery orders are eligible, and a randomized experiment tests whether a proactive delivery update reduces customer support contacts. Every step shows the document, query, notebook, evaluation table, experiment plan or decision readout that carries the work.
The data scientist role and team
What a data scientist does at work, from an uncertain business question to checked evidence and a decision
How the data scientist role differs from the data analyst, analytics engineer, data engineer and machine learning engineer, and why titles and boundaries vary between companies
Who owns product decisions, methods review, data contracts, production models and privacy review, and how to reach them
How to frame a business question as a decision, population, outcome, guardrails and acceptance test
The workday and the week
How exploration, coding, reviews, meetings and written updates fit into a data scientist workday
How planning, stand-up, methods review, experiment review and product decision readouts connect across the week
How to make Jupyter notebooks reproducible, request peer review and hand work to another role
Core data science work
Exploratory data analysis (EDA) with SQL and Python: grain, missing values, duplicates, distributions and event-time order
A/B test design: randomization, hypotheses, sample size and power, primary metrics, guardrail metrics and a decision rule locked before launch
Forecasting with time-aware validation, a seasonal naive baseline, forecast error and uncertainty
Prediction versus causal questions, and how to match every claim to the evidence that supports it
A data science project from question to decision
Write an approved analysis plan with a label, prediction time, eligible population, outcome and review gates
Build a feature dataset without data leakage, with chronological train, validation and test periods
Compare a baseline and a candidate model with precision, recall, calibration, slice checks and a decision threshold
Analyze the experiment with effect size, confidence interval and guardrails, and present a decision readout
Tools, vocabulary and failures
Python, pandas, JupyterLab and GitHub for reproducible analysis
Snowflake, BigQuery, Databricks and dbt, and how warehouses, lakehouse notebooks and tested transformations fit together
scikit-learn, statsmodels, Power BI, Tableau, Looker and experiment platforms, shown as tool categories without ranking
The vocabulary of experiments, model evaluation, forecasting, workflow and causal inference
How a team detects feature leakage, handles experiment imbalance and broken notebooks, and fixes them safely
Before day one and interviews
Skills and portfolio projects to practice before your first data science job
A first 90 days plan: learn the business, reproduce existing work, deliver reviewed evidence and own one improvement
How to answer data scientist interview questions and approach practical coding, statistics, experiment and forecasting exercises
Practical tools you can use at work
Apply what you learn with downloadable PDF guides and Excel workbooks, including:
Data Scientist Team Contact Map
Meetings, Experiment Reviews, and Decision Readouts Guide
Data Science Analysis and Model Work Templates
Data Scientist Job Vocabulary
Experiment and Model Incident Card
Data Scientist Skills Self-Check and 90-Day Plan
Data Scientist Interview Preparation Guide
Experiment, Model, Forecast, and Tool Map
Who this course is for
Students and graduates who want to see what a data scientist job involves day to day
Data analysts, engineers and researchers moving toward applied data science
Career switchers preparing for a first data scientist role
New data scientists who want a clear picture of team workflows, reviews and handoffs
Job seekers preparing for data scientist interviews and practical exercises