Learner Resource 7Sampling methods mix and match

Task: You need three different coloured highlighters or colouring pencils for this task. Firstly read the study outline below:

An experimenter wants to conduct a study to investigate if there is a correlation between personality and length of mobile phone text messages. 20 students aged 16–19 were used.Personality was assessed by asking the participant to rate themselves using a scale of 1 (very introvert – shy) to 10 (very extrovert-outgoing). The average number of words used in a text message over a period of one week was obtained from their phones.

For each sampling method there is explanation how the researcher could use the method in this research, strength in a P.E.C format and a weakness in a P.E.C format. You must identify which box matches the sampling method – use a different colour for each sampling method. Please note: P.E.C is a suggested format.

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Research methods

Type of sampling method

How this could be used in the study

Strength – Point Example/Evidence Comment Weakness –

PointExample/Evidence Comment

Random sampling The researcher could visit a local college and ask the first 20 students he sees who fit the criteria to take part in the study which will investigate personality and length of mobile phone text message. They will be asked to rate their personality on a scale of 1-10 and their mobile phones will be analysed.

One strength of using this method is that you gain a wide access to the participants as the advertisement is open to the public.

This is because all names of students at the school had an equal chance of being selected by the computer generator to take part in the study looking at personality and the length of mobile phone text messages.

Using a random sample is good as it would prevent gaining a bias sample as the researcher cannot select more preferable participants to take part therefore results would be higher in validity.

One weakness is that it is a unrepresentative sample and often biased by the researcher may be selective about the participants he chooses.

For example, not all students will use Facebook therefore only certain types of students will respond to the advertisement about the study on personality and mobile phone text messages. e.g. more social able students.

This is a bias method, as people tend not to respond to adverts etc. unless they have a strong interest/view to share or a motivation to take part therefore are more likely to respond with demand characteristics.

Self-selected sampling

The researcher could access the school database and use a number generator to select a sample. The researcher would contact the participants and ask them if they will take part in the study which will investigate personality and length of mobile phone text message and then asked to rate their personality on a scale of 1-10 and their mobile phones will be analysed.

One strength of using this method is that every member of the target population has an equal chance of being selected.

For example, the researcher could stand in the corridor of the school and approach the first 20 students he sees to ask if they will participate in a study looking at personality and length of mobile phone messages they send.

As people are responding to the advert ethical concerns are low as it leads to informed consent.

One weakness is that the target population may be too large.

For example, the researcher may choose people who are appear friendly or make eye contact with them to take part in the study looking at personality and length of mobile phone text messages.

Therefore it is very difficult and time consuming to do, especially with large target populations.

Opportunity sampling

Interested?

Interested?

The researcher could place an advertisement on a Facebook page for students to take part in a study investigating personality and length of mobile phone text messages. Participants will then asked to rate their personality on a scale of 1–10 and their mobile phones will be analysed.

One strength of using this method is that it is the quickest and easiest way to obtain participants.

This is because the advertisement will be placed on a Facebook page asking for participants to take part in a study looking at personality and the length of mobile phone messages and viewed and accessed to a variety of people.

Opportunity sampling is good as it is the most economical way of obtaining participants.

A weakness could be that it is difficult and time consuming to advertise and contact the participants to take part.

For example, the experimenter may experience difficulties accessing the student data base at to find the participants to take part in the study on personality and length of mobile phone text messages.

So it is likely to produce a bias sample as the sample and therefore not very representative.

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Research methods

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