Lesson 6 - Sampling methods

Question 1

Strengths of random sampling

Answer 1

There is no researcher bias when selecting the sample because it has been chosen by chance with no conscious choice from the researcher. Equal chance of being picked

Question 2

Weaknesses of random sampling

Answer 2

Might be impractical with very large groups, like assigning a number to 100s of people

Question 3

What is systematic sampling?

Answer 3

Taking every 10th person from a list, for example.

Question 4

Strengths of systematic sampling

Answer 4

Far more simple than random sampling.

Less time consuming than random sampling.

Question 5

Weaknesses of systematic sampling

Answer 5

Some may refuse to take part, dramatically decreasing the size of the sample

Question 6

Strengths of stratified sampling

Answer 6

Representative of the population, more generalisable

Question 7

Weaknesses of stratified sampling

Answer 7

Can be time consuming as the categories need to be identified and then calculated as proportions. You also need details on all the people in the relevant strata.

Question 8

What is opportunity sampling?

Answer 8

Involves selecting participants who are readily available and willing to take part. Could be people they know quite well, or people they have contact to

Question 9

Strengths of opportunity sampling

Answer 9

This is the most practical and easy method of getting a sample together.

Question 10

Weaknesses of opportunity sampling

Answer 10

There is a high chance that the sample is unrepresentative of the target population. Some people may just feel obliged to take part because they know you personally, even if they do not really want to. So this is unethical.

Question 11

What is volunteer sampling

Answer 11

The investigator will put out an ad or ask for people to participate and people will come forward to participate. Can be done through TV ads, posters, radios etc.

Question 12

Strengths of volunteer sampling

Answer 12

Saves the researcher themselves time and effort. All they need to do is construct an ad for the study and then wait. This is better than other sampling methods like stratified sampling where the investigator needs to calculate proportions of the strata.

Question 13

Weaknesses of volunteer sampling

Answer 13

A certain type of person needs to volunteer - enthusiastic, willing, interested in the topic. Therefore there is a very high chance that the sample obtained will be unrepresented as it will not reflect the target population (volunteer bias).