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Build a complete sample space

About 9 minutes · 3 reading + 6 practice and checks
Time includes reading, practice, and questions. Extra videos or further study are optional.
See this course’s project requirements

A chance-model packet with a complete sample space, combined-event calculations, conditional probabilities and a repeated-trial comparison.

Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.

What to include

  • List a complete equal-outcome sample space.
  • Calculate a complement and an independent combined event.
  • Audit overlap in an inclusive-or event.
  • Compare conditional and unrestricted denominators.
  • Explain observed frequency versus theoretical chance with all six changed cases.

Review and revise

Use these criteria to check your work and choose what to improve.

  • Method: applies the course-specific rules to the supplied cases with visible intermediate work.
  • Accuracy: results agree with the stated facts, units, boundaries and independent checks.
  • Reasoning: explains why the result follows and identifies a limitation or unresolved question.
  • Transfer: completes changed cases and revises the final project when a relevant assumption changes.
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Before you begin

The idea in everyday life

Case: one fair coin and one fair three-sector spinner labeled 1,2,3; independent mechanisms. Outcomes record coin then spinner.

The idea

A sample space lists all possible outcomes under a stated model. Counts become probabilities only when outcomes are equally likely. Define the experiment and the outcome being counted before dividing.

Follow along

Build a complete sample space — worked practice

A sample space lists all possible outcomes under a stated model. Counts become probabilities only when outcomes are equally likely. Define the experiment and the outcome being counted before dividing.

Case: one fair coin and one fair three-sector spinner labeled 1,2,3; independent mechanisms. Outcomes record coin then spinner.

Original practice material

Paste at A1.

AMaterialBSupplied text
CaseCase: one fair coin and one fair three-sector spinner labeled 1,2,3; independent mechanisms. Outcomes record coin then spinner.

Copy as plain text
  1. 1. 1. List

    Pair each coin side with each spinner number.

    You should see: H 1, H 2, H 3, T 1, T 2, T 3.

  2. 2. 2. Count

    Check that all pairs appear once.

    You should see: Six equally likely outcomes.

  3. 3. 3. Select

    List outcomes with heads and spinner number 2.

    You should see: H 2 only.

  4. 4. 4. Calculate

    Divide favorable outcomes by all equally likely outcomes.

    You should see: Probability 1/6.

Now change one thing

Use a fair coin and a four-sector fair spinner. Enter the total number of paired outcomes.

Your work

What to finish

A complete sample-space list with one favorable-event probability.

Common mistake

Watch for this

The simple count rule assumes equal likelihood. Unequal areas require appropriate probability weights rather than equal sector counts.

How can I tell I understand it?

Construct a changed paired sample space without treating unequal sectors as equally likely.

Try 3 questions

Quick knowledge check

Answer all 3 questions. Get at least 2 right and the lesson completes automatically.

Not yet passed

You’ll get an explanation for each answer. Signed in? Your results save to your account.

1A fair coin and a fair five-sector spinner create how many paired outcomes?
2In the supplied six-outcome space, what is the chance of spinner number 2?
3A spinner has unequal sector areas. Why is favorable-count/sector-count insufficient?
0 of 3 answeredApply the lesson to a short question, then review the explanation.
1
Finish this lesson

Pass the check. We’ll save the progress.

Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.

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Sources and further reading

Explore the references behind this lesson.

OpenStax: probability terminology
Source & access notes · checked 2026-10-01

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Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.

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