Sampling

Front 1

Random Sampling

Back 1

Every member has an equal chance of being selected.

E.g. Pulling names out if as hat or using a lottery technique

Front 2

Systematic sampling

Back 2

Using a predetermined system with a target population.

E.g. Selecting every 10th person from the phone book

Front 3

Stratified and quota Sampling

Back 3

Dividing the target population into important subcategories. Selecting members in proportion that they occur in.

E.g. 2.5% of British are of Indian origin so 2.5% of your sample should be of Indian origin.

Front 4

Opportunity Sampling

Back 4

Selecting thosse people who are available at the time.

E.g. Going up to people in a cafe and asking them to be interviewed.

Front 5

Self seleted (Volunteer) sampling

Back 5

Individuals who have been chosen to be involved in the study. Also called volunteer.

E.g. People who responded to an advert for participants

Front 6

Strengths of systematic sampling

Back 6

Unbiased as participants are selected from an objective system.

Front 7

Weaknesses of systematic sampling

Back 7

Not completely random

Not everyone has an equal chance of people picked

Front 8

Strengths of stratified and quota sampling

Back 8

A deliberate effort is made to make the sample population representative of the target population

More respresentative than opportunity sampling as there is a equal representation of subgroups

Front 9

Weaknesses of stratified sampling

Back 9

It can be time consuming as subcategories have to be identified and proportions calculated

Same weaknesses of random and opportunity sampling

Front 10

Strengths of random sampling

Back 10

For every large sample it provided the best chance of an unbiased representative sample

All members of the teacher population have an equal chance of being selected

Front 11

Strengths of opportunity sampling

Back 11

Quick, convenient and economical. A most common type of sampling in practice.

Front 12

Weakness of opportunity sampling

Back 12

Very unrepresentative samples and often biased by the researcher who will likely choose people who are 'helpful'.

Will be biased as you will only be selecting from a small subgroup of the target population.

Front 13

Self selected (volunteer) sampling

Back 13

Relatively convenient and ethical if it leads to informed consent.

Assess to a wide variety of participants, which could lead to a more representative sample.

Front 14

Weaknesses of self selected (volunteer) sampling

Back 14

Unrepresentative as it leads to bias on the part of participant.

E.g. day time TV adverts would not attract full time workers

Sample will be biased becaause participants are more likely to be highly motivated