1. a.
|
Department
|
Number of people
|
Number on Committee
|
| Marketing |
85
|
2 |
| Manufacturing |
470
|
12
|
| Design |
60
|
2
|
| Packaging |
120
|
3
|
| Dispatch |
90
|
2
|
| Administration |
175
|
4
|
b. Each person in the department is given a number and random numbers selected within that range to choose the number of people needed.
2. Answers depend on individual choices.
3. a. A population is the whole of the group under investigation and a sample is a part or subset of the population.
b. A systematic sample is where a person or item is selected at intervals from a population. Acluster sample is where a sample is collected from particular groups taken from a population.
4.
|
Year Level
|
Number of students
|
% of total roll
|
Number of students in sample*
|
|
Year 8
|
150
|
17.6
|
9
|
|
Year 9
|
180
|
21.2
|
11
|
|
Year 10
|
200
|
23.5
|
12
|
|
Year 11
|
180
|
21.2
|
11
|
|
Year 12
|
140
|
16.5
|
8
|
|
Totals
|
850
|
100
|
51
|
* Total of students in sample do not add up to 50 due to rounding.
5. a. A census is when every member of a population is surveyed and a sample survey is when only part of the population is surveyed.
b. A random sample is probably the best method, making sure that fans from all over the ground and of all ages are chosen.
6 a. If you assume that every athlete has an equal chance of finishing third, then the method is quite random, but in terms of drug testing you are probably better to test ALL medal winners and certainly the gold medal winners.
b. Even for just predicting the voters intentions in the city this method is not very good, as people walking the main street at lunchtime will probably be people with jobs who are happy having just had lunch so the sample would probably produced biased results! The people in the city may vote completely different from other towns. A sample of people chosen from all round the country would be more representative.
c. This would produce a random sample from the 40 people, as we have to assume that the Lotto balls are selected randomly.
d. Quite random but missing the people who have telephones but are not listed in the directory.
|
7
|
Randomness
|
Bias
|
|
a
|
Not random because only students who use that gate at that time can be chosen. | Bias could occur because people arriving at that time may all get one particular type of transport. |
|
b
|
Random as every student is on the list. | Unbiased. |
|
c
|
Not every student may be at home and not every home may have a telephone. | It could be biased as you may choose a night when certain groups of students may be out, say, at a social or sport practice. |
|
d
|
Not random as you are only selecting from Year 12 students. | Biased as Year 12 students may prefer a certain type of transport and may have access to cars which younger student do not. |
8. The response rate from this type of survey is generally low. The people who fill in the registration form may not be typical of all of the people buying the program. However for a survey of this type this method should be quite informative for the company.
|
9
|
Randomness
|
Reason
|
|
a
|
Not particularly random. |
People who can afford the time and money to watch a rugby game may be a bit happier than those who cannot. Unless you are a rugby fan at that particular game you cannot be selected for the sample |
|
b
|
Quite random | Random for telephone owners listed in the book but those who don't have a phone or have an unlisted number cannot be chosen. |
|
c
|
Not random | Only people who work in the building could be chosen and they may be from a particular income range or group and so their views may be biased. |
|
d
|
Almost random | Random unless anyone forgot to register or were only temporarily in Canberra and were registered in another district. |
