Psychology: Selecting Participants

What is a target population?
-Group of people who share a given characteristic which the researcher will draw a conclusion from
-->Usually too large so a REPRESENTATIVE SAMPLE will be taken, used to generalise

Sample types?
1)RANDOM SAMPLE
2)NON RANDOM SAMPLE: 1) SELF SELECTED SAMPLE 2)OPPERTUNITY SAMPLE

Random sample?
Everybody within the target population has equal chance of being chosen
-->doesnt guarentee unbiased representation

NRS: self- selected samples?
-Participants volunteer on their own accord
-->yet this may not be representative of the TYPICAL behaviour, potential bias

NRS: Oppertunity samples?
-Research selects whoever is avaliable at the time from any population
-->biased, unlikely to be fully representative as not all SUBGROUPS are avaliable

RELATIONSHIP BETWEEN RESEARCHERS AND PARTICIPANTS:

What are demand characteristics?
-These appear when an individual attempts to make sense of the research situation
--->then attempts to act accordingly

Signs of demand characteristics?
1)GUESS RESEARCH PURPOSE: thus trying to act in a helpful way
2)NERVOUSNESS: feeling they are being evaluated
3)SOCIAL DESIRABILITY: wanting to be seen in a desirable light

Investigator effect?

-Effect of the researchers behaviour/characteristics on the investigation:
-->EXPECTATION EFFECTS
-->FRAUD: "massaging data"
-->Naturalistic observational studies
----->observer presense
----->questionnaires/interviewers: age, sex, expression, appearance