Data Collection

Question 1

Define population

Answer 1

A whole set of data/items that are of interest

Question 2

Define census

Answer 2

Observes or measures every member of a population

Question 3

Define sample

Answer 3

Selection of observations taken from a subset of the population

Question 4

What are the advantages of a census?

Answer 4

Should always give you a completely accurate result

Question 5

What are disadvantages of a census?

Answer 5

Time consuming, expensive, cannot be used if the testing process destroys the item and hard to process large quantities of data

Question 6

What are the advantages of a sample?

Answer 6

Less time consuming and expensive than a census, fewer people have to respond and there is less data to process than a census

Question 7

What are the disadvantages of a sample?

Answer 7

Data may not be accurate and the sample may not be large enough to give information about small subset groups of a population

Question 8

What are sample units?

Answer 8

Individual units of a population

Question 9

What is a sampling frame?

Answer 9

A list of all the items you want to study in your population

Question 10

What are the characteristics of random sampling?

Answer 10

Every member of the population has an equal chance, sample should be representative and it helps to remove bias

Question 11

What are the three methods of random sampling?

Answer 11

Simple random sampling, systematic sampling and stratified sampling

Question 12

What do you need to carry out simple random sampling?

Answer 12

A sampling frame

Question 13

What are the two methods of choosing numbers?

Answer 13

Generating random numbers and lottery sampling

Question 14

In systematic sampling, how are elements chosen?

Answer 14

Regular intervals from an ordered list meaning that there are equal gaps between those who are chosen

Question 15

In stratified sampling, how is the population divided?

Answer 15

Into mutually exclusive strata

Question 16

What should the ratio of each strata be?

Answer 16

1:1 meaning that each strata sample should be equal

Question 17

How do you calculate the number of sampled in a stratum?

Answer 17

(Number of stratum/number of population) x overall sample size

Question 18

What are the advantages of simple random sampling?

Answer 18

Free of bias, easy and cheap to implement for small populations/samples and each sampling unit is known and has an equal chance of selection

Question 19

What are the disadvantages of simple random sampling?

Answer 19

Not suitable when population size/sample size is too large and a sampling frame is needed

Question 20

What are the advantages of systematic sampling?

Answer 20

Simple, quick to use and suitable for large populations/samples

Question 21

What are the disadvantages of systematic sampling?

Answer 21

Sampling frame needed and it can introduce bias if the sampling frame is not random

Question 22

What are the advantages of stratified sampling?

Answer 22

Accurately reflects the population structure and guarantees proportional representation of groups within a population

Question 23

What are the disadvantages of stratified sampling?

Answer 23

Population must be clearly classified into district strata and selection within each strata suffers from the same disadvantages as simple random sampling (sample frame needed and not suitable for large sample size due to expense and time)

Question 24

What are the two types of non-random sampling?

Answer 24

Quota sampling and opportunity sampling

Question 25

What happens in quota sampling?

Answer 25

An interviewer or researcher selects a sample that reflects the characteristics of a whole population and they are divided into groups based on given characteristics

Question 26

What does the size do each quota sampling group determine?

Answer 26

It determines the proportion of the sample that should have that characteristic

Question 27

What happens if in quota sampling a person refuses to be interviewed?

Answer 27

You ignore them and move on

Question 28

What happens in opportunity sampling?

Answer 28

You take a sample from people who are available at the time to be studied and who fit your criteria

Question 29

What is opportunity sampling also known as?

Answer 29

Convenience sampling

Question 30

What are the advantages of quota sampling?

Answer 30

Allows a small sample to represent the population, no sampling frame needed, quick. easy and inexpensive and it always easy comparison between different groups within a population

Question 31

What are the disadvantages of quota sampling?

Answer 31

Could lead to bias, population must be divided into groups which is costly and inaccurate, non-responses are not recorded and increasing scope of study increases number of groups adding time and expense

Question 32

What are the advantages of opportunity sampling?

Answer 32

Easy to carry out and inexpensive

Question 33

What are the disadvantages of opportunity sampling?

Answer 33

Unlikely to provide a representative sample and highly dependent on individual researcher

Question 34

Describe quantitative data

Answer 34

Data associated with numerical observations

Question 35

Describe qualitative data

Answer 35

Associated with non-numerical observations

Question 36

Describe continuous variable

Answer 36

Can take any value in a given range

Question 37

Describe discrete variable

Answer 37

Can take only specific values in a given range

Question 38

Describe class boundaries

Answer 38

Maximum and minimum values in class

Question 39

Describe midpoints

Answer 39

Average of the class boundaries

Question 40

Describe class width

Answer 40

Difference between upper and lower class boundaries