Data Science & Analytics Topics
Statistical analysis, data analytics, big data technologies, and data visualization. Covers statistical methods, exploratory analysis, and data storytelling.
Causal Inference and Treatment Effects
Cover principles and methods for estimating causal effects from experimental and observational data. Topics include the difference between correlation and causation, randomized experiments and A B testing, confounding and identification, propensity score matching, inverse probability weighting, instrumental variables, regression discontinuity, difference in differences, and estimation of heterogeneous treatment effects. Discuss assumptions required for identification, common pitfalls, and how causal estimates are used to inform policy and product interventions.
Exploratory Data Analysis
Exploratory Data Analysis is the systematic process of investigating and validating a dataset to understand its structure, content, and quality before modelling or reporting. Core activities include examining schema and data types, computing descriptive statistics such as counts, means, medians, standard deviations and quartiles, and measuring class balance and unique value counts. It covers distribution analysis, outlier detection, correlation and relationship exploration, and trend or seasonality checks for time series. Data validation and quality checks include identifying missing values, anomalies, inconsistent encodings, duplicates, and other data integrity issues. Practical techniques span SQL profiling and aggregation queries using GROUP BY, COUNT and DISTINCT; interactive data exploration with pandas and similar libraries; and visualization with histograms, box plots, scatter plots, heatmaps and time series charts to reveal patterns and issues. The process also includes feature summary and basic metric computation, sampling strategies, forming and documenting hypotheses, and recommending cleaning or transformation steps. Good Exploratory Data Analysis produces a clear record of findings, assumptions to validate, and next steps for cleaning, feature engineering, or modelling.
Causal Inference and Confounding
Foundational concepts and methods for reasoning about cause and effect and for estimating causal effects from experimental and observational data. Topics include the distinction between correlation and causation, causal graphs and directed acyclic graphs, sources of confounding bias, randomized experiments, instrumental variable approaches, difference in differences, regression discontinuity designs, propensity score methods, sensitivity analysis, diagnostics for assumptions, and considerations for external validity and transportability.
Statistical Foundations for Experimentation
Core statistical concepts and inference needed to design analyze and interpret experiments. Topics include hypothesis testing p values confidence intervals Type One and Type Two errors the relationship between sample size variability and interval width statistical power minimum detectable effect and effect size versus practical significance. Candidates should be able to choose and explain common statistical tests such as t tests and chi square tests contrast Bayesian and frequentist approaches at a conceptual level and describe variance estimation and variance reduction techniques. The topic covers corrections for multiple comparisons sequential testing and the risks of peeking and p hacking common misconceptions about p values and limitations of inference such as confounding and selection bias. Candidates should also be able to translate statistical findings into clear language for non technical stakeholders and explain uncertainty and limitations.
A/B Test Results Analysis
Learn to analyze results from A/B tests and experiments. Understand key statistics: sample size, statistical significance, confidence intervals, and p-values at a practical level (not deep theory). Practice interpreting test results: 'Is this difference real or just noise?' Learn common mistakes: stopping tests early, p-hacking, and running too many tests simultaneously.
Metrics, Guardrails, and Evaluation Criteria
Design appropriate success metrics for experiments. Understand primary metrics, secondary metrics, and guardrail metrics. Know how to choose metrics that align with business goals while avoiding unintended consequences.
Data Storytelling and Insight Communication
Skills for converting quantitative and qualitative analysis into a clear, persuasive narrative that guides stakeholders from findings to action. This includes leading with the headline insight, defining the business question, selecting the most relevant metrics and visual evidence, and structuring a concise story that explains what happened, why it happened, and what the recommended next steps are. Candidates should demonstrate tailoring of language and technical depth for diverse audiences from engineers to product managers to executives, summarizing trade offs and uncertainty in plain language, distinguishing correlation from causation, proposing follow up experiments or investigations, and producing concise executive summaries and status reports with an appropriate cadence. Interviewers evaluate the ability to persuade and align cross functional partners, answer questions about data validity and methodology, synthesize qualitative signals with quantitative results, and adapt presentation format and level of detail to the decision maker.
Business Impact Measurement and Metrics
Selecting, measuring, and interpreting the business metrics and outcomes that demonstrate value and guide decisions. Topics include high level performance indicators such as revenue decompositions, lifetime value, churn and retention, average revenue per user, unit economics and cost per transaction, as well as operational indicators like throughput, quality and system reliability. Candidates should be able to choose leading versus lagging indicators for a given question, map operational KPIs to business outcomes, build hypotheses about drivers, recommend measurement changes and define evaluation windows. Measurement and attribution techniques covered include establishing baselines, experimental and quasi experimental designs such as A B tests, control groups, difference in differences and regression adjustments, sample size reasoning, and approaches to isolate confounding factors. Also included are quick back of the envelope estimation techniques for order of magnitude impact, converting technical metrics into business consequences, building dashboards and health metrics to monitor programs, communicating numeric results with confidence bounds, and turning measurement into clear stakeholder facing narratives and recommendations.
Probability and Statistical Inference
Covers fundamental probability theory and statistical inference from first principles to practical applications. Core probability concepts include sample spaces and events, independence, conditional probability, Bayes theorem, expected value, variance, and standard deviation. Reviews common probability distributions such as normal, binomial, Poisson, uniform, and exponential, their parameters, typical use cases, computation of probabilities, and approximation methods. Explains sampling distributions and the Central Limit Theorem and their implications for estimation and confidence intervals. Presents descriptive statistics and data summary measures including mean, median, variance, and standard deviation. Details the hypothesis testing workflow including null and alternative hypotheses, p values, statistical significance, type one and type two errors, power, effect size, and interpretation of results. Reviews commonly used tests and methods and guidance for selection and assumptions checking, including z tests, t tests, chi square tests, analysis of variance, and basic nonparametric alternatives. Emphasizes practical issues such as correlation versus causation, impact of sample size and data quality, assumptions validation, reasoning about rare events and tail risks, and communicating uncertainty. At more advanced levels expect experimental design and interpretation at scale including A B tests, sample size and power calculations, multiple testing and false discovery rate adjustment, and design choices for robust inference in real world systems.