# WST02/01 October 2016

> WST02/01 October 2016: 7 questions, 75 marks. Difficulty 0.40, deviation 0.16, algebraic 0.31, text density 0.35. Edexcel IAL Mathematics S2.

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Edexcel IAL · Mathematics · 2016 October

This Statistics 2 (WST02) paper contains 7 questions worth 75 marks. The profile below reports five mark-weighted difficulty and complexity measures, and every question row repeats them. Full question text and mark scheme open in the Interactive Practice Hub.

- Edexcel IAL
- S2
- 7 questions
- 75 marks
- Free paper
- [Practise this paper](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555)
- [All S2 papers](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/)

Core finding

**WST02/01 October 2016 is a past paper for Edexcel IAL Statistics 2 (WST02), with 7 questions worth 75 marks.** Its mark-weighted Difficulty Measure is 0.40 on a 0.20–0.75 scale, with a Difficulty Deviation of 0.16 and a mark split of 29.3% Easy, 57.4% Medium and 13.3% Hard. Algebraic complexity averages 0.31; text density and modelling average 0.35. All five measures use 26 part-level tags, not candidate results. Every question row below repeats them and opens the Interactive Practice Hub for that question.

## Difficulty & complexity profile

All five measures are mark-weighted and calculated from 26 parts carrying 75 part marks. Difficulty tags cover 26 parts, algebraic tags 26 and text-density tags 26. Tags are internal metadata, not official exam-board ratings.

- **Difficulty Measure**: 0.40 — 0.20–0.75 · nearer Medium
- **Difficulty Deviation**: 0.16 — 0 = uniform; higher = more mixed
- **Difficulty Ratio**: 29.3 / 57.4 / 13.3 — % Easy / Medium / Hard
- **Algebraic Complexity Measure**: 0.31 — 0.20–0.75 · nearer Low
- **Text Density and Modelling Measure**: 0.35 — 0.20–0.75 · nearer Medium

Scale: Easy 0.20 · Medium 0.45 · Hard 0.75, and Low 0.20 · Medium 0.45 · High 0.75 for the two complexity measures. [How each band is defined and how the values are calculated →](https://www.examsci.com/guides/difficulty-and-complexity-measures/)

### Definitions and calculation

| Measure | Paper value | Formula |
| --- | --- | --- |
| **Difficulty Measure** | 0.40 | Σ(d_i × w_i) / Σw_i, with d = 0.20 / 0.45 / 0.75 |
| **Difficulty Deviation** | 0.16 | √(Σw_i(d_i − μ)^2 / Σw_i) |
| **Difficulty Ratio** | 29.3% Easy / 57.4% Medium / 13.3% Hard | marks in band / all tagged marks |
| **Algebraic Complexity Measure** | 0.31 | Σ(c_i × marks_i) / Σmarks_i, with c = 0.20 / 0.45 / 0.75 |
| **Text Density and Modelling Measure** | 0.35 | Σ(t_i × marks_i) / Σmarks_i, with t = 0.20 / 0.45 / 0.75 |

w_i equals the part marks, except for a Hard part worth 4 or more marks, where w_i = marks^0.75 to offset the accessible starter steps inside long structured questions.

## Question list

Each measure is recalculated from the parts of that question and uses the same weights as the paper profile.

| Question | Topic | Marks | Difficulty Measure | Algebraic Complexity Measure | Text Density and Modelling Measure | Practice |
| --- | --- | --- | --- | --- | --- | --- |
| **Q1** FRQ | [4. Hypothesis tests](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/hypothesis-tests/) | 10 | 0.45 Medium | 0.20 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=cb6b6e78-17fa-46a4-bb30-dbcfd0193da3&source_detail=WST02%2F01+October+2016) |
| **Q2** FRQ | [2. Continuous random variables](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/continuous-random-variables/) | 14 | 0.33 Medium | 0.25 Low | 0.20 Low | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=2e0d74ec-cf62-422a-b438-ed5d1741f7e8&source_detail=WST02%2F01+October+2016) |
| **Q3** FRQ | [1. The Binomial and Poisson distributions](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/the-binomial-and-poisson-distributions/) | 10 | 0.38 Medium | 0.20 Low | 0.30 Low | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=808ca1bf-0f3a-4e97-8425-4c85edd26c4d&source_detail=WST02%2F01+October+2016) |
| **Q4** FRQ | [2. Continuous random variables](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/continuous-random-variables/) | 10 | 0.38 Medium | 0.38 Medium | 0.20 Low | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=e0902b12-7620-431b-847a-3e91b9110632&source_detail=WST02%2F01+October+2016) |
| **Q5** FRQ | [3. Continuous distributions](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/continuous-distributions/) | 11 | 0.36 Medium | 0.29 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=573679f1-d363-40ca-938e-f5cdb42139b1&source_detail=WST02%2F01+October+2016) |
| **Q6** FRQ | [1. The Binomial and Poisson distributions](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/the-binomial-and-poisson-distributions/) | 12 | 0.45 Medium | 0.52 Medium | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=24890e11-a43c-460a-878e-31c6e0e2c748&source_detail=WST02%2F01+October+2016) |
| **Q7** FRQ | [4. Hypothesis tests](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/hypothesis-tests/) | 8 | 0.56 Medium | 0.29 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=c63e980b-bb97-49fe-81c9-cd74781ea555&question_id=6e7e2000-1144-4f39-a9e0-857953239a78&source_detail=WST02%2F01+October+2016) |

## Topics in this paper

- [4. Hypothesis tests](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/hypothesis-tests/)
- [1. The Binomial and Poisson distributions](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/the-binomial-and-poisson-distributions/)
- [2. Continuous random variables](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/continuous-random-variables/)
- [3. Continuous distributions](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-2-wst02/continuous-distributions/)

## Related papers

- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2016-june-wst02-01/) — June 2016 — 7 questions · 75 marks — Free
- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2016-january-wst02-01/) — January 2016 — 7 questions · 75 marks — Free
- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2017-october-wst02-01/) — October 2017 — 6 questions · 75 marks — Free
- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2017-june-wst02-01/) — June 2017 — 7 questions · 75 marks — Free
- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2017-january-wst02-01/) — January 2017 — 7 questions · 75 marks — Free
- [WST02/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2015-june-wst02-01/) — June 2015 — 7 questions · 75 marks — Free

## Paper FAQ

**How are the difficulty and complexity measures calculated?**

Each part is weighted by its official marks. Difficulty uses Easy 0.20, Medium 0.45 and Hard 0.75; algebraic complexity and text density and modelling use Low 0.20, Medium 0.45 and High 0.75. A Hard part worth 4 or more marks is down-weighted to marks^0.75, so the accessible starter steps inside a long structured question do not inflate the difficulty result. This paper's Difficulty Measure is 0.40 from 26 parts.

**What does the Difficulty Deviation show?**

It is the mark-weighted standard deviation of the part difficulty values around the paper mean. A value of 0 would mean every tagged part has the same difficulty; this paper's deviation is 0.16, so its parts are more mixed than a single-level paper.

**Is the Difficulty Ratio based on question counts or marks?**

It is based on official marks, not question counts. This paper's shares are 29.3% Easy, 57.3% Medium and 13.3% Hard; the three shares sum to 100% before rounding.

**Are these official difficulty ratings?**

No. They are derived from the platform's part-level difficulty and static-question-profile tags. They are not exam-board grade boundaries and are not calculated from candidate outcomes. Use them to compare the demand profile of papers, not to predict a grade.

**Why does each question row show its own measures?**

Each row recalculates the same mark-weighted formula from that question's parts. A single-part MCQ therefore shows the tag value directly, while a multi-part structured question blends the tags of its parts using the same Hard-part decay as the paper profile.

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Full page with native tables, bar charts and Practice Hub links: https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-2-wst02/2016-october-wst02-01/