| Exam Board | CAIE |
|---|---|
| Module | S2 (Statistics 2) |
| Year | 2015 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Data representation |
| Type | Select random sample using random numbers |
| Difficulty | Easy -1.8 This question tests basic understanding of sampling methods and reading random number tables - purely recall-based with no calculation or problem-solving. Part (i) requires listing standard criticisms of convenience sampling (e.g. bias, not random), while part (ii) simply asks students to describe the mechanical process of extracting two-digit numbers from a random number string, which is a routine textbook procedure. |
| Spec | 2.01c Sampling techniques: simple random, opportunity, etc2.01d Select/critique sampling: in context |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Marks | Guidance |
| E.g. Only students who use canteen | B1 | Or any reason that some are excluded |
| The five will probably be friends | B1 [2] | B1 each sensible reason must be in context |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Marks | Guidance |
| 2-digits | B1 | |
| ignore > 82 (anything too big) | B1 | |
| Ignore repeats | B1 [3] |
## Question 1:
### Part (i)
| Answer | Marks | Guidance |
|--------|-------|----------|
| E.g. Only students who use canteen | B1 | Or any reason that some are excluded |
| The five will probably be friends | B1 [2] | B1 each sensible reason must be in context |
### Part (ii)
| Answer | Marks | Guidance |
|--------|-------|----------|
| 2-digits | B1 | |
| ignore > 82 (anything too big) | B1 | |
| Ignore repeats | B1 [3] | |
---1 Jyothi wishes to choose a representative sample of 5 students from the 82 members of her school year.\\
(i) She considers going into the canteen and choosing a table with five students from her year sitting at it, and using these five people as her sample. Give two reasons why this method is unsatisfactory.\\
(ii) Jyothi decides to use another method. She numbers all the students in her year from 1 to 82 . Then she uses her calculator and generates the following random numbers.
$$231492 \quad 762305 \quad 346280$$
From these numbers, she obtains the student numbers $23,14,76,5,34$ and 62 . Explain how Jyothi obtained these student numbers from the list of random numbers.
\hfill \mbox{\textit{CAIE S2 2015 Q1 [5]}}