Populations and Samples

Question 1

What are the advantages of census data?

Answer 1

• It should give a completely accurate result

Question 2

What are the disadvantages of census data?

Answer 2

• Time consuming and expensive

- Hard to process a large quantity of data

Question 3

What are the advantages of sample data?

Answer 3

It- Less time consuming and expensive than a census

• Fewer people have to respond
• Fewer data to process than a census.

Question 4

What are the disadvantages of sample data?

Answer 4

• The data may not be as accurate

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

Question 5

What are the individual units of a population known as?

Answer 5

• Sampling units

Question 6

When sampling units of a population are individually named what are they called?

Answer 6

• Sampling frame

Question 7

What are the three main ways of sampling data?

Answer 7

• Simple random sampling
• Systematic sampling
• Stratified sampling

Question 8

What is simple random sampling?

Answer 8

• Where every size n has an equal chance of being selected.

Question 9

How do you carry out simple random sampling?

Answer 9

• Allocate people a number

- Then generate the random number (lottery sampling)

Question 10

What is systematic sampling?

Answer 10

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

Question 11

Give an example of systematic sampling

Answer 11

• If sample 20 was required from a population of 100, you would take every fifth person since 100 / 20 = 5.

Question 12

What is stratified sampling?

Answer 12

-The population is divided into mutually exclusive strata( males and females ) and a random sample is taken from each.

Question 13

What are the advantages of simple random sampling?

Answer 13

• Free of bias
• Easy and cheap to implement
• Each sampling unit has a known and equal chance of selection.

Question 14

What are the disadvantages of simple random sampling?

Answer 14

• Not suitable when the population size or the sample size is large.
• A sampling frame is needed.

Question 15

What are the advantages of systematic sampling?

Answer 15

• Simple and quick to use

- Suitable for large samples and large populations

Question 16

What are the disadvantages of systematic sampling?

Answer 16

• A sampling frame is needed

- It can introduce bias if the sampling frame is not random

Question 17

What are the advantages of stratified sampling?

Answer 17

• Sample accurately reflects the population structure

- Guarantees proportional representation of groups within a population.

Question 18

What are the disadvantages of stratified sampling?

Answer 18

• Population must be clearly classified into distinct strata.

Question 19

What are the two methods of non-random sampling?

Answer 19

• Quota sampling

- Opportunity sampling

Question 20

What is another name for ‘Opportunity sampling’?

Answer 20

• convenience sampling

Question 21

What are the advantages of Quota sampling?

Answer 21

• Allows a small sample to still be a representation of the population
• No sampling frame is required
• Quick, easy, and inexpensive.

Question 22

What are the disadvantages of Quota sampling?

Answer 22

• Non-random sampling can introduce bias.

- Population must be divided into groups, which can be inaccurate.

Question 23

What is opportunity sampling?

Answer 23

• Opportunity sampling consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for.

Question 24

What is quota sampling?

Answer 24

• In quota sampling, an interviewer or researcher selects a sample that reflects the characteristics of the whole population.