experimental design Flashcards
experimental design
the way that participants are allocated to the levels of the IV
3 types
1)independent measures
2)repeated
3)matched pair
independent
design in which a different group of participants is used
for each level of the IV
why do we use random allocation
high participant variables
are there demand characteristics
no
what are demand characteristics
features that give away the aim
reduces validity
random allocation
helps avoid participant variables everyone has equal chance of getting picked (hat)
strengths of indep
1-no order effects
2-no demand characteristics
3-random allocation reduces participation variables
weaknesses of indep
1-partispant varibles
2-more participants are needed
repeated
A repeated measures design is an experimental design in
which each participant performs in every level of the IV.
participant variables
individual differences that can effect results
order effects
happen when a task is being performed more than once
types of order effects
1-practice: improves because they did it once before
2-fatigue: performance declines gets worse due to boredom or tiredness
randomisation
way to overcome order effects
counterbalancing
is a way to overcome order effects where each possible order of levels of the IV preformed in sub groups
ad of repeated
-Eliminates any participant
variables as all of them take
part in all conditions
-fewer participants
dis of repeated
-There is a chance of demand
characteristics as participants
may work out the aim or
change their behaviour.
-Order effects can affect the
findings of the study and
reduce its validity. This could
be overcome using
counterbalancing.
matched pairs
is an experimental design in
which participants are arranged in pairs. Each pair is
similar in ways that are important to the study and one
member of each pair performs in a different level of the
IV.
strengths of matched
-no demand
-no order effects
-no participant variables
weakness of matched
1-Trying to match people
exactly is impossible as there
will always be individual
differences from one person
to another.
-The sample may be smaller
as trying to find a large
sample of people matching
across similar traits may be
difficult. This may mean the
findings may lack external
validity.
