Chapter 1 - data collection

Question 1

what is a population?

Answer 1

the whole set of items that are of interest

Question 2

what is a census?

Answer 2

observes or measures every member of a population

Question 3

what is a sample?

Answer 3

selection of observations taken from a subset of the population which is used to find out about the population

Question 4

what is a sampling unit?

Answer 4

individual units of a population

Question 5

what is a sampling frame?

Answer 5

sampling units of a population which are individually named or numbered from a list

Question 6

what is a simple random sample of size n

Answer 6

every sample of size n has equal chance of being selected

Question 7

what is systematic sampling?

Answer 7

required elements chosen at regular intervals from list

Question 8

what is stratified sampling?

Answer 8

population divided into mutually exclusive strata and random sample taken from both

Question 9

quota sampling>

Answer 9

interviewer or research selects sample that reflects whole population

Question 10

what is opportunity sampling?

Answer 10

taking sample from people who are available at the time and who fit criteria

Question 11

What does quantative variables/ data mean?

Answer 11

associated with numerical observations

Question 12

What are qualitative data?

Answer 12

non numerical data

Question 13

what is a continuous variable?

Answer 13

can take any value in given range

Question 14

what is a discrete variable?

Answer 14

variable only taking specific values

Question 15

what are class boundaries?

Answer 15

max + min values in each class

Question 16

what is the class width?

Answer 16

difference between upper and lower class boundaries

Question 17

Advantages of a census

Answer 17

• it should give a completely accurate result

Question 18

disadvanatages of a census

Answer 18

• time consuming and expensive
• cannot be used when the testing process destroys the item
• hard to process large quantity of data

Question 19

advantages of a sample?

Answer 19

• less time consuming and expensive then a census
• fewer people have to respond
• less data to process than in a census

Question 20

disadvantages of a sample?

Answer 20

• the data may not be accurate

- the sample may not be large enough to give information about small sub groups of the population