# WST01/01 June 2018

> WST01/01 June 2018: 7 questions, 75 marks. Difficulty 0.38, deviation 0.15, algebraic 0.28, text density 0.37. Edexcel IAL Mathematics S1.

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Edexcel IAL · Mathematics · 2018 June

This Statistics 1 (WST01) 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
- S1
- 7 questions
- 75 marks
- Free paper
- [Practise this paper](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8)
- [All S1 papers](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/)

Core finding

**WST01/01 June 2018 is a past paper for Edexcel IAL Statistics 1 (WST01), with 7 questions worth 75 marks.** Its mark-weighted Difficulty Measure is 0.38 on a 0.20–0.75 scale, with a Difficulty Deviation of 0.15 and a mark split of 33.3% Easy, 58.7% Medium and 8.0% Hard. Algebraic complexity averages 0.28; text density and modelling average 0.37. All five measures use 31 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 31 parts carrying 75 part marks. Difficulty tags cover 31 parts, algebraic tags 31 and text-density tags 31. Tags are internal metadata, not official exam-board ratings.

- **Difficulty Measure**: 0.38 — 0.20–0.75 · nearer Medium
- **Difficulty Deviation**: 0.15 — 0 = uniform; higher = more mixed
- **Difficulty Ratio**: 33.3 / 58.7 / 8.0 — % Easy / Medium / Hard
- **Algebraic Complexity Measure**: 0.28 — 0.20–0.75 · nearer Low
- **Text Density and Modelling Measure**: 0.37 — 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** | 0.38 | Σ(d_i × w_i) / Σw_i, with d = 0.20 / 0.45 / 0.75 |
| **Difficulty Deviation** | 0.15 | √(Σw_i(d_i − μ)^2 / Σw_i) |
| **Difficulty Ratio** | 33.3% Easy / 58.7% Medium / 8.0% Hard | marks in band / all tagged marks |
| **Algebraic Complexity Measure** | 0.28 | Σ(c_i × marks_i) / Σmarks_i, with c = 0.20 / 0.45 / 0.75 |
| **Text Density and Modelling Measure** | 0.37 | 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. Correlation and regression](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/correlation-and-regression/) | 13 | 0.35 Medium | 0.26 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=e4d2ad08-bf7c-4042-a0e2-a794c347b7f2&source_detail=WST01%2F01+June+2018) |
| **Q2** FRQ | [2. Representation and summary of data](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/representation-and-summary-of-data/) | 11 | 0.36 Medium | 0.20 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=ec77862c-db7e-49c2-980a-ea18bfa8fbe3&source_detail=WST01%2F01+June+2018) |
| **Q3** FRQ | [3. Probability](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/probability/) | 7 | 0.27 Easy | 0.20 Low | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=d92a3dd8-f137-4edd-8ded-6f59766301b6&source_detail=WST01%2F01+June+2018) |
| **Q4** FRQ | [5. Discrete random variables](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/discrete-random-variables/) | 10 | 0.28 Easy | 0.28 Low | 0.20 Low | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=dca26e36-103a-4ea0-9fb5-78bac0d8af17&source_detail=WST01%2F01+June+2018) |
| **Q5** FRQ | [2. Representation and summary of data](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/representation-and-summary-of-data/) | 13 | 0.41 Medium | 0.32 Low | 0.43 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=544826b4-7d74-4973-8c9b-021d3ad3a164&source_detail=WST01%2F01+June+2018) |
| **Q6** FRQ | [6. The Normal distribution](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/the-normal-distribution/) | 9 | 0.62 Hard | 0.37 Medium | 0.45 Medium | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=a530796e-4969-42e9-b97c-5478fc9b2215&source_detail=WST01%2F01+June+2018) |
| **Q7** FRQ | [3. Probability](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/probability/) | 12 | 0.41 Medium | 0.30 Low | 0.20 Low | [Go to Practice Hub](https://www.examsci.com/practice?set_id=4623222d-7332-4dbd-9d37-2435c34c54b8&question_id=896c55b2-60aa-44c9-806f-fcb2f9f3e8fc&source_detail=WST01%2F01+June+2018) |

## Topics in this paper

- [4. Correlation and regression](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/correlation-and-regression/)
- [2. Representation and summary of data](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/representation-and-summary-of-data/)
- [3. Probability](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/probability/)
- [5. Discrete random variables](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/discrete-random-variables/)
- [6. The Normal distribution](https://www.examsci.com/topics/edexcel-ial/mathematics/statistics-1-wst01/the-normal-distribution/)

## Related papers

- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2018-october-wst01-01/) — October 2018 — 6 questions · 75 marks — Free
- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2018-january-wst01-01/) — January 2018 — 7 questions · 75 marks — Free
- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2019-october-wst01-01/) — October 2019 — 7 questions · 75 marks — Free
- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2019-june-wst01-01/) — June 2019 — 6 questions · 75 marks — Free
- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2019-january-wst01-01/) — January 2019 — 6 questions · 75 marks — Free
- [WST01/01](https://www.examsci.com/past-papers/edexcel-ial/mathematics/statistics-1-wst01/2017-october-wst01-01/) — October 2017 — 6 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 0.38 from 31 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 0.15, 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 33.3% Easy, 58.7% Medium and 8.0% 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-1-wst01/2018-june-wst01-01/