The analyst’s toolkit, in six short lessons.

From choosing between the mean and the median to sizing an A/B test and building a guesstimate out loud. Each step asks you to predict first, then shows real numbers: a shop’s tables on PostgreSQL, a 5,000-customer table and our calculator’s own arithmetic. About 52 minutes in all, free, with no sign-up.

6 lessons30 steps31 interview questions

  1. 1Statistics you use every dayMost of an analyst’s statistics is choosing the right summary: the mean or the median, a percentile, a rate, and spotting the values that don’t belong.About 8 minutes · 5 steps
  2. 2SQL that answers questionsMost of an analyst’s questions are a JOIN, a GROUP BY and a filter.About 10 minutes · 5 steps
  3. 3Charts that answer the questionA chart is an answer to a question.About 8 minutes · 5 steps
  4. 4Power BI’s filter contextIn Power BI, a measure has no single value: it’s worked out again for every cell, under whatever filters apply there.About 9 minutes · 5 steps
  5. 5A/B testsAn A/B test answers whether a change made a difference.About 9 minutes · 5 steps
  6. 6GuesstimatesInterviewers ask “how many UPI payments does a restaurant take on a Saturday?” not for the number but for how you reach it.About 8 minutes · 5 steps

Start with lesson 1

Built from real data.

  • Predict, then see

    Every step starts with a question to guess. Guessing first, then checking, makes an idea stick far better than reading it.

  • Real data

    SQL run on PostgreSQL, statistics and charts from a 5,000-customer table through pandas, A/B numbers from our calculator’s own code. The few made-up figures say so.

  • Ready for interviews

    Each lesson ends with the interview questions it prepares you for, their answers in our bank, and practice with Prism.