sampling methods

Question 1

Population

Answer 1

A group of people who are the focus of the researcher’s interest, from which a smaller sample is drawn

Question 2

Sample

Answer 2

A group of people who take part in a research study. THe sample is drawn from a target population and is presumed to be representative of the population

Question 3

Types of sampling methods

Answer 3

Random
Systematic
Stratified sampling
Opportunity sampling
Volunteer sampling

Question 4

Random sample

Answer 4

every member of the target population has an equal chance of being selected

Question 5

How to carry out random sampling

Answer 5

To select the sample first complete a list of all members of the target population.Secondly all names are assigned a number. Thirdly the sample is generated through the use of lottery methods (number generator or picking numbers from hats)

Question 6

Strengths of random sampling

Answer 6

Free from researcher bias as researcher has no influence over who is selected and this prevents them from choosing people who they think may support their hypothesis.

Question 7

Limitations of random sampling

Answer 7

-Is difficult and time consuming
-you may still end up with a unrepresentative sample(e.g.more boys than girls)
-PPT may refuse to take part

Question 8

Systematic sampling

Answer 8

Every nth person is chosen from a list
A sampling frame is produced which is a list of people in the target population. A sampling system is nominated (every 4th or 8th person) or this interval may be determined randomly to reduce bias

Question 9

Strengths of systematic sampling

Answer 9

• Avoids researcher bias as researcher as no influence over who is chosen

Question 10

limitation of systematic sampling

Answer 10

Not truly unbiased unless you select a number using a random method and start with this person and then select every nth person

Question 11

Stratified random

Answer 11

-the proportions of people in population sub groups (strata) are reflected in the sample.

Question 12

Strengths of stratified sampling

Answer 12

-Likely to be more representative than other methods because there is a proportional and randomly selected representation of subgroups

Question 13

limitation of stratified sampling

Answer 13

-Very time consuming to identify subgroups then randomly select ppt and contact them.

Question 14

opportunity sampling

Answer 14

-whoever is available at the time of sampling will be included,

Question 15

+ of opp sampling

Answer 15

-the easiest method because you just use the first suitable participants you can find, which means less time to locate your sample than if using one of the other techniques.

Question 16

• of opp sampling

Answer 16

-Biased because the sample is drawn from a small part of the population. If you pick people from a sample that is walking on a monday morning the sample will not include professionals as they would be at work.

Question 17

Volunteer

Answer 17

-Participants self select
-Advertise in a newspaper or on a noticeboard or on the internet

Question 18

Strength of volunteer sampling

Answer 18

Gives access to a variety of participants which may make the sample more representative and less biased

Question 19

limitation of volunteer sampling

Answer 19

-Sample is biased in other ways because ppt are likely to be more highly motivated and with extra time on their hands. They might be more highly motivated to be helpful or more broke and needing money offered for participation. This results in volunteer bias