Sampling

Question 1

what is a population?

Answer 1

the whole set of items that are of interest

Question 2

what is raw data?

Answer 2

the information obtained from a population

Question 3

what is a census?

Answer 3

data collected from the entire population

Question 4

what is a sample?

Answer 4

some subset of the population intended to represent it

Question 5

what is a sampling unit?

Answer 5

each individual thing in the population that can be sampled

Question 6

what is a sampling frame?

Answer 6

when sampling units are individually named/numbered to form a list

Question 7

what are the advantages of a census?

Answer 7

it should give completely accurate results

Question 8

what are the advantages of sampling

Answer 8

1. cheaper
2. quicker
3. there is less data to process

Question 9

what are the disadvantages of a census?

Answer 9

1. it can’t be used when testing involves destruction
2. time consuming
3. expensive
4. there is a large amount of data to process

Question 10

what are the disadvantages of sampling?

Answer 10

1. may not be as accurate
2. the sample may not be large enough to represent small subgroups

Question 11

what are the types of random sampling?

Answer 11

1. simple random sampling
2. systematic sampling
3. stratified sampling

Question 12

how do you conduct simple random sampling?

Answer 12

1. a sampling frame must be created using numbers or names
2. then a random number generator or lottery sampling should be used to select the things that will be included in the sample

Question 13

how do you conduct systematic sampling?

Answer 13

1. sampling frame must be created
2. then the required elements from the sampling frame are chosen at regular intervals until sample is created

Question 14

how do you determine which item to begin with in systematic sampling?

Answer 14

use simple random sampling/ random generator

Question 15

how do you determine the interval for systematic sampling?

Answer 15

divide the population size by the sample size

Question 16

how do you conduct stratified sampling?

Answer 16

1. strata are created using the population
2. simple random sampling is used within each stratum to determine which items of each stratum will be used

Question 17

how do you determine how many items from each stratum is included?

Answer 17

1. divide the number of items in the stratum by the number of items in the entire population
2. then multiply that by the total sample size

Question 18

when is stratified sampling used?

Answer 18

when the sample required is large and the population naturally divides into groups

Question 19

what are the advantages of simple random sampling?

Answer 19

1. free from bias
2. simple
3. cheap
4. each item has an equal chance of being selected

Question 20

what are the advantages of systematic sampling?

Answer 20

1. simple
2. quick
3. suitable for large samples or populations

Question 21

what are the advantages of stratified sampling?

Answer 21

1. reflects population structure
2. guarantees proportional representation of groups within the population

Question 22

what is a stratum?

Answer 22

a group within the population

Question 23

what are the disadvantages of simple random sampling?

Answer 23

1. not suitable for large populations
2. sampling frame is needed

Question 24

what are the disadvantages of systematic sampling?

Answer 24

1. sampling frame is needed
2. can introduce bias if the sampling frame isn’t random

Question 25

what are the disadvantages of stratified sampling?

Answer 25

1. the population must be clearly classified into groups 2. sampling frame is needed within stratums

Question 26

how do you conduct quota sampling?

Answer 26

1. divide population into strata based on their characteristics of interest 2. determine the amount of people from each strata that will be included in the sample

Question 27

how do you determine the amount of items that will be sampled in quota sampling?

Answer 27

people within each group are actively chosen by an interviewer until the quota is filled

Question 28

how do you conduct opportunity sampling?

Answer 28

A sample is taken from people who are available at the time of the study, who meet the criteria

Question 29

what are the advantages of quota sampling?

Answer 29

1. it allows small samples to represent the population 2. no sampling frame is needed 3. quick 4. cheap 5. simple 6. it allows easy comparisons between different groups in a population

Question 30

what are the advantages of opportunity sampling?

Answer 30

1. simple 2. cheap

Question 31

what are the disadvantages of quota sampling?

Answer 31

1. can introduce bias 2. population must be divided into groups which can often be inaccurate 3. as the population size increases the cost and time also increases 4. non-responses are not recorded

Question 32

what are the disadvantages of opportunity sampling?

Answer 32

1. unlikely to provide a representative sample 2. dependent on the individual researcher