Edexcel IAL · Mathematics · WST01 · Discrete random variables
Topic Questions: 5.3 Mean and variance of a discrete random variable. — WST01 Discrete random variables
120 WST01 Discrete random variables topic questions are tagged to this syllabus point across 36 papers (2014–2026). Only the parts whose knowledge graph matches this syllabus statement are counted, and the table shows which parts of each question are involved.
Core finding
This Discrete random variables syllabus point appears in 36 WST01 papers across 2014–2026, contributing 120 topic questions and 326 marks. The most recent appearance is WST01/01 January 2026. That equals 52.9% of the 227 topic questions and 59.3% of the 550 marks tagged to Discrete random variables. Only parts tagged to this subtopic are counted, so a four-part question can contribute one item and one part's marks. The table lists every matching question, its tagged parts and marks, with a link back to the paper page. Sessions are newest first, so the statement can be traced back through the full paper history.
Topic questions by session
Newest sessions first. Parts and marks count only the parts tagged to this subtopic; “x of y parts” shows how much of the question is tagged elsewhere. Select the paper cell to open the matching question on the paper page, or use Go to Practice Hub to answer that exact question in the Interactive Practice Hub.
| Paper | Question | Type | Parts | Marks | Difficulty | Practice |
|---|---|---|---|---|---|---|
| WST01/01January 2026 · Edexcel IAL | Q4 Discrete Random Variables and Cumulative Distribution - Edexcel IAL S1 Jan 2026 Q4 |
FRQ | 2 of 6 parts ((b)(i), (b)(ii)) | 7 of 13 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2026 · Edexcel IAL | Q6 Discrete Uniform Distribution - Edexcel IAL S1 Jan 2026 Q6 |
FRQ | 2 of 3 parts ((b), (c)) | 8 of 10 on the paper |
Easy | Go to Practice Hub |
| WST01/02January 2026 · Edexcel IAL | Q1 Discrete Random Variables - Jan 2026 Q1 |
FRQ | 2 of 3 parts ((b), (c)) | 5 of 6 on the paper |
Easy | Go to Practice Hub |
| WST01/02January 2026 · Edexcel IAL | Q6 The Normal Distribution - Jan 2026 Q6 |
FRQ | 1 of 2 parts ((b)) | 4 of 9 on the paper |
Hard | Go to Practice Hub |
| WST01/01October 2025 · Edexcel IAL | Q3 Fair 6-sided Die Discrete Uniform Distribution |
FRQ | 1 of 3 parts ((c)) | 3 of 6 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2025 · Edexcel IAL | Q4 Discrete Probability Distribution with Unknown Constants |
FRQ | 2 of 4 parts ((a), (d)) | 7 of 10 on the paper |
Medium | Go to Practice Hub |
| WST01/02October 2025 · Edexcel IAL | Q6 Expectation and Variance of Discrete DRVs - Edexcel IAL S1 October 2025 Q6 |
FRQ | 4 of 6 parts ((a), (b)(i), (b)(ii), (c)) | 9 of 13 on the paper |
Easy | Go to Practice Hub |
| WST01/01June 2025 · Edexcel IAL | Q1 Discrete Random Variables - Edexcel IAL June 2025 S1 Q1 |
FRQ | 3 of 5 parts ((c), (d), (e)) | 6 of 9 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2025 · Edexcel IAL | Q1 Discrete Random Variables and Distributions - Edexcel IAL S1 Jan 2025 Q1 |
FRQ | 3 of 8 parts ((c)(i), (c)(ii), (d)) | 5 of 15 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2024 · Edexcel IAL | Q6 Discrete Random Variables and Biased Dice - Edexcel IAL S1 Oct 2024 Q6 |
FRQ | 3 of 6 parts ((c), (d), (e)) | 8 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01June 2024 · Edexcel IAL | Q2 Discrete Random Variables - Edexcel IAL Statistics S1 June 2024 Q2 |
FRQ | 2 of 4 parts ((b), (c)) | 7 of 12 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2024 · Edexcel IAL | Q7 Discrete Random Variable Cumulative Distribution - Edexcel IAL S1 Jan 2024 Q7 |
FRQ | 1 of 4 parts ((d)) | 5 of 10 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2023 · Edexcel IAL | Q4 Discrete Random Variables, Expectation, and Variance - Edexcel IAL Statistics S1 Oct 2023 Q4 |
FRQ | 4 of 5 parts ((a), (b), (c)(i), (c)(ii)) | 7 of 12 on the paper |
Medium | Go to Practice Hub |
| WST01/01June 2023 · Edexcel IAL | Q5 Discrete Random Variables - Edexcel IAL S1 Jun 2023 Q5 |
FRQ | 2 of 5 parts ((c), (e)) | 6 of 13 on the paper |
Medium | Go to Practice Hub |
| WST01/01January 2023 · Edexcel IAL | Q3 Discrete Random Variables and Expectation - Edexcel IAL S1 January 2023 Q3 |
FRQ | 3 parts ((a), (b), (c)) | 11 | Medium | Go to Practice Hub |
| WST01/01October 2022 · Edexcel IAL | Q4 Expected Value of Discrete Random Variable - Edexcel IAL S1 Oct 2022 Q4 |
FRQ | 1 part | 4 | Medium | Go to Practice Hub |
| WST01/01October 2022 · Edexcel IAL | Q7 Discrete Probability Distribution and Multi-variable Joint Events - Edexcel IAL S1 Oct 2022 Q7 |
FRQ | 3 of 6 parts ((b), (c), (d)) | 6 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01June 2022 · Edexcel IAL | Q5 Discrete Random Variables - Expected Values, Probability Distributions, and Game Probability |
FRQ | 3 of 6 parts ((a), (b), (d)) | 8 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2022 · Edexcel IAL | Q1 Venn Diagrams and Probability - Edexcel IAL S1 Jan 2022 Q1 |
FRQ | 1 of 6 parts ((f)) | 3 of 11 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2022 · Edexcel IAL | Q4 Discrete Uniform Distribution - Edexcel IAL S1 Jan 2022 Q4 |
FRQ | 3 of 6 parts ((b), (d)(ii), (e)) | 9 of 13 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2021 · Edexcel IAL | Q4 Probability Tree Diagram and Discrete Random Variables - Edexcel IAL S1 Oct 2021 Q4 |
FRQ | 1 of 5 parts ((e)) | 2 of 13 on the paper |
Medium | Go to Practice Hub |
| WST01/01October 2021 · Edexcel IAL | Q5 Discrete Random Variables and Pythagoras - Edexcel IAL S1 Oct 2021 Q5 |
FRQ | 2 of 4 parts ((a), (c)) | 5 of 14 on the paper |
Medium | Go to Practice Hub |
| WST01/01June 2021 · Edexcel IAL | Q5 Discrete Random Variables - Edexcel IAL S1 Jun 2021 Q5 |
FRQ | 4 of 5 parts ((a), (b), (c)(i), (c)(ii)) | 10 of 15 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2021 · Edexcel IAL | Q4 Discrete Uniform Distribution & Random Variables - Edexcel IAL S1 Jan 2021 Q4 |
FRQ | 5 of 7 parts ((b)(i), (b)(ii), (c)(i), (c)(ii), (d)) | 13 of 16 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2020 · Edexcel IAL | Q1 Discrete Random Variables - Edexcel IAL S1 Oct 2020 Q1 |
FRQ | 1 part | 5 | Medium | Go to Practice Hub |
| WST01/01October 2020 · Edexcel IAL | Q6 Discrete and Normal Distributions - Edexcel IAL S1 Oct 2020 Q6 |
FRQ | 3 of 7 parts ((a), (b), (d)) | 6 of 15 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2020 · Edexcel IAL | Q1 Discrete Random Variables - Probability Distribution with Unknowns |
FRQ | 1 part | 5 | Medium | Go to Practice Hub |
| WST01/01January 2020 · Edexcel IAL | Q6 Discrete Random Variables and Expected Profit |
FRQ | 3 of 6 parts ((b), (c), (f)) | 10 of 17 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2019 · Edexcel IAL | Q7 Discrete Random Variables - Edexcel IAL Statistics S1 Oct 2019 Q7 |
FRQ | 4 parts ((a), (b), (c), (d)) | 15 | Medium | Go to Practice Hub |
| WST01/01June 2019 · Edexcel IAL | Q5 Biased Spinner Discrete Random Variable - Edexcel IAL S1 Jun 2019 Q5 |
FRQ | 2 of 5 parts ((a), (b)) | 7 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2019 · Edexcel IAL | Q2 Discrete Probability Distribution - Edexcel IAL S1 Jan 2019 Q2 |
FRQ | 3 parts ((a), (b), (c)) | 10 | Medium | Go to Practice Hub |
| WST01/01October 2018 · Edexcel IAL | Q5 Discrete Random Variables, CDF and Linear Transformations - Edexcel IAL S1 Oct 2018 Q5 |
FRQ | 1 of 4 parts ((c)) | 6 of 14 on the paper |
Medium | Go to Practice Hub |
| WST01/01June 2018 · Edexcel IAL | Q4 Discrete Random Variables - Edexcel IAL S1 June 2018 Q4 |
FRQ | 3 of 5 parts ((c), (d), (e)) | 7 of 10 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2018 · Edexcel IAL | Q4 Discrete Random Variables and Distributions - Edexcel IAL S1 Jan 2018 Q4 |
FRQ | 4 of 6 parts ((a), (b)(i), (b)(ii), (c)) | 9 of 13 on the paper |
Medium | Go to Practice Hub |
| WST01/01October 2017 · Edexcel IAL | Q6 Discrete random variables and expectations - Edexcel IAL S1 Oct 2017 Q6 |
FRQ | 3 of 8 parts ((d), (e), (g)) | 8 of 17 on the paper |
Medium | Go to Practice Hub |
| WST01/01June 2017 · Edexcel IAL | Q6 Discrete random variables - Edexcel IAL S1 June 2017 Q6 |
FRQ | 2 of 7 parts ((c), (d)) | 5 of 17 on the paper |
Medium | Go to Practice Hub |
| WST01/01January 2017 · Edexcel IAL | Q4 Discrete Random Variables - Edexcel IAL S1 Jan 2017 Q4 |
FRQ | 4 of 6 parts ((a), (b), (c), (d)) | 8 of 13 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2016 · Edexcel IAL | Q2 Discrete Random Variables - Edexcel IAL S1 Oct 2016 Q2 |
FRQ | 6 of 8 parts ((b), (c)(i), (c)(ii), (d), (f)(i), (f)(ii)) | 11 of 15 on the paper |
Easy | Go to Practice Hub |
| WST01/01October 2016 · Edexcel IAL | Q5 Weight of Jam Jars - Edexcel IAL S1 Oct 2016 Q5 |
FRQ | 1 of 2 parts ((b)) | 4 of 11 on the paper |
Hard | Go to Practice Hub |
| WST01/01June 2016 · Edexcel IAL | Q3 Discrete Uniform Distribution Properties - Edexcel IAL S1 June 2016 Q3 |
FRQ | 4 of 8 parts ((e), (f), (g), (h)) | 9 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2016 · Edexcel IAL | Q1 Discrete Random Variables - Edexcel IAL S1 Jan 2016 Q1 |
FRQ | 4 of 6 parts ((b), (c), (d)(i), (d)(ii)) | 8 of 12 on the paper |
Easy | Go to Practice Hub |
| WST01/01June 2015 · Edexcel IAL | Q6 Discrete Uniform Distribution - Edexcel IAL S1 June 2015 Q6 |
FRQ | 3 of 6 parts ((b), (c), (e)) | 6 of 9 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2015 · Edexcel IAL | Q6 Discrete Probability Function - Edexcel IAL S1 Jan 2015 Q6 |
FRQ | 3 of 5 parts ((c), (d), (e)) | 10 of 14 on the paper |
Easy | Go to Practice Hub |
| WST01/01June 2014 · Edexcel IAL | Q5 Discrete Random Variable with Unknowns - Edexcel IAL Statistics S1 June 2014 Q5 |
FRQ | 5 of 6 parts ((a), (b), (c), (d), (e)) | 11 of 15 on the paper |
Easy | Go to Practice Hub |
| WST01/01January 2014 · Edexcel IAL | Q4 Discrete Random Variables - Edexcel IAL S1 Jan 2014 Q4 |
FRQ | 2 of 4 parts ((a), (d)) | 8 of 11 on the paper |
Medium | Go to Practice Hub |
Related topic questions in Discrete random variables
Topic question rules and edge cases
- How many topic questions cover this syllabus point?
- 45 question stems cover this subtopic across 36 papers, but only 120 tagged parts and 326 marks belong to it. Other parts of the same questions are assessed under different statements and are excluded from this page.
- Which papers include this subtopic?
- The table lists every matching session from 2014–2026. Each row links to the question anchor on the paper page, where the full paper context and practice entry point are available.
- Why can one question appear under several subtopics?
- The parts of one question can assess different syllabus statements. Each part is counted under its own subtopics, so the same question stem can appear on several subtopic pages while each page lists only the parts and marks tagged to that statement.
- Can I practise these questions with AI marking?
- Yes. Open a paper from the table and use the Interactive Practice Hub entry point. The page itself is static HTML so search engines and retrieval agents can read the full question list without executing JavaScript.