Data Collection

Question 1

Census

Answer 1

Observes or measure every member of a population

Question 2

Sample

Answer 2

Selection of observations taken from subset of the population which is used to find out information about the population as a whole

Question 3

Advantage of census

Answer 3

Gives a completely accurate result

Question 4

Disadvantages of a census

Answer 4

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

Question 5

Advantages of Sample

Answer 5

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

Question 6

Disadvantages of Sampling

Answer 6

Data might not be accurate

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

Question 7

Simple random sample

Answer 7

Sample of size n is one where every sample of size n has an equal chance of being selected

Question 8

Systematic sampling

Answer 8

The required elements are chosen at regular intervals from an ordered list

Question 9

Stratified sampling

Answer 9

The population is divided into mutually exclusive strata and a sample is taken from each

Question 10

Advantages of simple random sampling

Answer 10

Free of bias
Easy+cheap to implement for small populations+small samples

Each sampling unit has a known + equal chance of selection

Question 11

Disadvantages of random sampling

Answer 11

Not suitable when population size or sample size is large as it is might be time consuming+ expensive

A sampling frame is needed

Question 12

Systematic sampling advantages

Answer 12

Simple and quick to use

Suitable for large samples and large populations

Question 13

Disadvantages of Systematic sampling

Answer 13

Sampling frame needed

Can be bias if sampling frame is not random

Question 14

Stratified sampling advantages

Answer 14

Accurately reflects population structure

Guarantees proportional representation of groups within a population

Question 15

Stratified sampling disadvantages

Answer 15

Population must be classified into distinct strata

Selection within each stratum suffers from the same disadvantages as simple random sampling

Question 16

Quota sampling

Answer 16

An interviewer or researcher selects a sample that reflects the characteristics pf the whole population

Question 17

Opportunity sampling

Answer 17

Consists of taking the sample from people who are available at the time of study is carried out + who fit the criteria you’re looking for

Question 18

Advantages of Quota Sampling

Answer 18

Allows small sample to represent population
No sampling frame needed
Quick,easy + inexpensive
Allows easy comparison between different groups of a population

Question 19

Disadvantages of quota sampling

Answer 19

Can introduce bias
Population must be divided into groups can be costly or inaccurate
Increasing scope of study increase number of study groups, adds time + expense
Non-responses aren’t recorded as such

Question 20

Advantages of opportunity sampling

Answer 20

Easy to carry out

Inexpensive

Question 21

Disadvantages of opportunity sampling

Answer 21

Unlikely to provide a representative sample

Very dependent on researcher