Sampling

Question 1

Census advantages

Answer 1

Should give a completely accurate result

Question 2

Census disadvantages

Answer 2

Time consuming and expensive
Hard to process large quantities of data
Can’t be used when the testing process destroys the item

Question 3

Sample advantages

Answer 3

Less time consuming than a census
Fewer people have to respond
Less data to process than a census

Question 4

Sample disadvantages

Answer 4

Data may not be as accurate
Sample may not be large enough to give info about small sub-groups of pop

Question 5

Simple random sampling advantages
(random sampling)

Answer 5

Free of bias
Easy and cheap to implement for small populations and small samples
Each sampling unit has a known and equal chance of selection

Question 6

Simple random sampling disadvantages
(random sampling)

Answer 6

Sampling frame needed
Not suitable when population size is too large

Question 7

Systematic sampling advantages
(random sampling)

Answer 7

Simple and quick to use
Suitable for large samples

Question 8

Systematic sampling disadvantages
(random sampling)

Answer 8

Sampling frame needed
Can introduce bias if sampling frame isn’t random

Question 9

Stratified sampling advantages
(random sampling)

Answer 9

Sample accurately reflects pop structure
Guarantees PR of groups within a population

Question 10

Stratified sampling disadvantages
(random sampling)

Answer 10

Population must be classified into distinct strata

Question 11

Quota Sampling advantages
(Non-random sampling)

Answer 11

Allows small sample to be representative of pop
No sampling frame
Quick and easy

Question 12

Quota Sampling disadvantages
(Non-random sampling)

Answer 12

Can introduce bias
Pop must be divided into groups - adds time and expense

Question 13

Opportunity sampling advantages
(Non-random sampling)

Answer 13

Easy to carry out
Inexpensive

Question 14

Opportunity sampling disadvantages
(Non-random sampling)

Answer 14

Unlikely to provide a representative sample
Highly dependent on individual researcher

Question 15

Process of simple random sampling

Answer 15

Need a sampling frame
Each person allocated a number
Number is chosen at random

Question 16

Process of systematic sampling

Answer 16

Required elements are chosen at regular intervals from an ordered list
e.g. if sample size was 20 from pop of 100 take every 5th person
First person taken at random

Question 17

Process of stratified sampling

Answer 17

Population divided into mutually exclusive strata (e.g. Male and Female)
Random sample taken from each

Question 18

Number sampled in a strata

Answer 18

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

Question 19

Process of quota sampling

Answer 19

Researcher selects a sample that reflects the characteristics of a whole pop

Question 20

Process of opportunity sampling

Answer 20

Taking sample from people who are available at the time of study and who fit the criteria