Statistics Quest

Applied Statistics for Professionals

Statistics as used in business, finance, HR, operations, marketing and research.

Sales and customer analysis, returns and risk, default rates, turnover and pay analysis, control charts and capability, funnels and cohorts, survey research, reading published results and public-health rates — each on a realistic (synthetic) dataset.

Lessons

  1. 1Sales performance and KPIsCalculate period and compound growth rates and make seasonality-aware sales comparisons that a manager can act on.30 minFree
  2. 2Customer behaviourSummarise baskets and customer spend honestly when the data are skewed, and compare customer segments without over-claiming.30 minMembers
  3. 3Returns, risk and volatilityDescribe the distribution of investment returns, measure and annualise volatility, and estimate a historical Value-at-Risk while stating what it cannot tell you.35 minMembers
  4. 4Default rates in lendingEstimate default rates with confidence intervals, compare them across segments, and interpret logistic-regression predictors of default without causal over-claims.35 minMembers
  5. 5Employee turnover and retentionCalculate turnover and churn rates with the right denominator, and analyse tenure data honestly when many people have not yet left (censoring).35 minMembers
  6. 6Pay percentiles and pay-equity foundationsBuild percentile pay bands, compute raw and adjusted pay gaps, and explain what an adjusted gap can and cannot tell you.40 minMembers
  7. 7Statistical process controlBuild X̄–R, I-MR, p, c and u control charts, apply the Western Electric rules, and tell a process signal from routine variation.40 minMembers
  8. 8Process capabilityCalculate Cp, Cpk, Pp and Ppk, translate them into expected nonconforming parts, and judge when a capability index can be trusted.35 minMembers
  9. 9Funnels and retention cohortsCompute funnel conversion rates and cost metrics with the right denominators, and build and read a cohort retention table.35 minMembers
  10. 10Survey researchCritique questionnaire items, summarise Likert data as ordinal, assess nonresponse and data quality, and weight survey results to the population.40 minMembers
  11. 11Reading published resultsExtract the estimate, its uncertainty and its practical size from a published result, check that the numbers agree with each other, and spot the red flags that should lower your trust.35 minMembers
  12. 12Rates and proportions in public healthCalculate and interpret prevalence, incidence rates per population and per person-time, screening accuracy and predictive values, and directly standardised rates that compare populations with different case mixes.40 minMembers