S2 January 2008 Q1
1.
(a) Explain what you understand by a census. (1)
Each cooker produced at GT Engineering is stamped with a unique serial number.
GT Engineering produces cookers in batches of 2000. Before selling them, they test a random sample of 5 to see what electric current overload they will take before breaking down.
(b) Give one reason, other than to save time and cost, why a sample is taken rather than a census. (1)
(c) Suggest a suitable sampling frame from which to obtain this sample. (1)
(d) Identify the sampling units. (1)
| Scheme | Marks |
|---|---|
| A census is when every member of the population is investigated. | B1 |
| (1) |
Notes
B1 Need one word from each group
(1) Every member /all items / entire /oe
(2) population/collection of individuals/sampling frame/oe
enumerating the population on its own gets B0
| Scheme | Marks |
|---|---|
| There would be no cookers left to sell. | B1 |
| (1) |
Notes
B1 Idea of Tests to destruction. Do not accept cheap or quick
| Scheme | Marks |
|---|---|
| A list of the unique identification numbers of the cookers. | B1 |
| (1) |
Notes
B1 Idea of list/ register/database of cookers/serial numbers
| Scheme | Marks |
|---|---|
| A cooker | B1 |
| (1) | |
| (4 marks) |
Notes
B1 cooker(s) / serial number(s)
The sample of 5 cookers or every 400th cooker gets B1