S3 June 2014 Q1
1.
(a) Explain what you understand by a random sample from a finite population. (1)
(b) Give an example of a situation when it is not possible to take a random sample. (1)
A college lecturer specialising in shoe design wants to change the way in which she organises practical work.
She decides to gather ideas from her 75 students.
She plans to give a questionnaire to a random sample of 8 of these students.
(c)
(i) Describe the sampling frame that she should use.
(ii) Explain in detail how she should use a table of random numbers to obtain her sample.
(3)| Scheme | Marks |
|---|---|
| (This is a sample where) every (possible) sample (of size \(n\)) has an equal chance of being chosen. | B1 |
| (1) |
Notes
Require all / each / every etc sample and same/equal etc chance / probability etc for B1
| Scheme | Marks |
|---|---|
| ‘When it is impossible to provide a sampling frame’ or a correct example with an indication of sampling frame being impossible. | B1 |
| (1) |
Notes
Require impossible / no / doesn’t exist etc and sampling frame for B1
| Scheme | Marks |
|---|---|
| (i) A list/register of all the students. | B1 |
| (ii) Number the students (from 0 to 74, 1 to 75 etc.) | B1 |
| Using the random no. table read off the nos. and identify or select the students allocated those nos. | B1 |
| (3) | |
| (5 marks) |
Notes
(i) Require list/register etc and all/every/75 etc students for B1
List of 8 students is B0
(ii) First B1 accept ‘in the corresponding position’ o.e. if numbering omitted
Second B1 require both for mark.