Variables
What are the four types of extraneous variable?
Situational, participant, demand characteristic, experimenter
What is a research aim
a statement of intent for a study "to investigate the effect of [independent variable] on [dependent variable]"
Name the types of experimental design
matched pairs, independent groups and repeated groups
What are the different sampling methods?
random, systematic, stratified, snowball, opportunity and volunteer
What is an independent variable
What changes - include both conditions
What is a hypothesis and what are the three types
a prediction of the results: null, directional and non-directional
What are order effects and how do you deal with them?
the effects of boredom, practice etc. that happen during repeated measures design. Dealt with by making conditions equally effected through counter balancing.
What are the two least generalisable ways to recruit participants
volunteer and opportunity
Which type of extraneous variables are reduced by using random allocation
experimenter variables
What is a strength of a field experiment?
high in ecological validity
What are participants matched on in the appropriate design?
matched pairs matches participants on a relevant characteristic to the study - age / IQ / proficiency etc.
Which is the msot representative way to select participants
stratified sampling
What are the type of extraneous variables that impact a field study?
Situational variables
when would it be appropriate to do a natural experiment over a lab experiment
when it would be impractical or unethical to manipulate the IV
What is a weakness of using each design
IM - participant variables
RM - order effects if not counter balanced
MP - still have some effect on participant variables and takes longer
How do you know if a study uses volunteers?
an advert / flyer would be used and volunteers contact the researcher to take part
Which extraneous variables impact results in an independent groups design but less so in a matched pairs design
Participant variables
How are experiments often analysed for descriptive statistics
Using the mean, median and mode
What is a strength of using each design
IG - random allocation to groups = fewer experimenter variables
MP - fewer participant variables
RG - Quicker to recruit Ps and fewer participant variabels
How do you know a study has used opportunity sampling?
the researcher approaches participants directly