Rullst AcademyRullst Academy/Lesson
Data, probability and statistics I · Lesson 01 / 12

A question worth investigating

Twelve fictional rovers deliver parts at Aurora station. Some arrive earlier than others. A well-chosen question helps more than a spreadsheet full of numbers.

Learning paths14 min

Let's discover together

  1. 1

    Check your preparation: 3 out of 4 is 75%; 2 + 4 + 6 = 12. If these relationships are confusing, revisit Mathematics: relationships for creating. Programming, installations and GitHub are not required.

  2. 2

    “How long does each of the 12 rovers’ deliveries take this shift?” expects different answers: it is a statistical question. “What is this rover’s name?” identifies a case but does not investigate a distribution of durations.

  3. 3

    The population of interest is the 12 deliveries this shift, not all future deliveries. Observing three produces a sample. A census observes every defined unit; even a census can have measurement errors or missing data.

  4. 4

    One row represents a delivery; id is a fictional identifier, group is route A/B and minutes is duration in minutes. Define when timing starts and ends before comparing. Numbers without units or context may answer a different question.

  5. 5

    Open the lab below, check the 12 records and write your question. Paper and the table also work. Use invented data only; real names, locations and classmates’ information are unnecessary.

Evidence lab

Experiment with fictional deliveries at Aurora station. Analysis runs in this browser. Nothing entered here is sent to the server.

The workshop resets when you leave or reload. Download data and report to keep your work, or send the report to the activity editor, which keeps a draft in this browser. Completion and XP belong to the account.

Header id,group,minutes; one delivery per row; unique id; groups A/B; decimal point; duration 0–1440 with up to two decimal places. Blank means unknown. Up to 100 rows. No quotes or decimal commas. Use invented data.

Selection uses the entered table, including missing values. A draw does not guarantee representativeness. The same seed reproduces selection; it cannot recover cases outside the table.

Make a prediction and analyze the table.

Virtual bag: model with replacement

There are four equally likely tokens; choose how many are blue. Each token returns before the next draw. This is a deterministic simulation, without prizes, money or real observations.

Repeating the seed repeats the sequence. More draws do not guarantee a closer result in every run and do not validate the real-world model.

Two rules, the same accuracy

Ten fictional cases: nine normal and one failure. Rules defined for this example; no AI training or real equipment testing. Same number correct, different consequences.

Two rules, the same accuracy
RuleCorrect / totalMissed failuresFalse alarms

Your investigation report

Official links and next step

✦
YOUR MISSION

Define a question, population, sample and unit before calculating.

Now it's your turn

Discovery workshop

Predict, check, explain

Define a question, population, sample and unit before calculating.
Build your answers and check when you are ready.
A moment to understand

Which question investigates variation between deliveries?

I need a hint

A statistical question anticipates variability and defines who the conclusion concerns. Counting rows alone does not define a population.

Loading your journey…

Take it with you

Invent a question about 20 missions on another shift. Define the observed unit, variable, measurement unit and which five cases would be observed first. Explain what that choice could miss.

At your own pace

My files and GitHub

Every lesson can become your own record: code, notes or a practice plan. Saving a file to GitHub is optional and does not change your XP.

Student guide

The editor and downloads open when this lesson is available to your account. Check access below or return to the track map.

Checking your access to this lesson…

Rullstpetbot

AI can make mistakes. Check the lesson material.