Experimental designs Flashcards
What is repeated measures?
1) Recruit a group of participants
2) Split them into two different conditions
3) Condition 1: the group does the experimental task with the IV set for condition 1
Condition 2: the group same repeats the experimental task with the IV set for condition 2
3) Compare the results for the two conditions
Name one weakness of repeated measures? (1)
one condition might be easier than the others
Name one weakness of repeated measures? (2)
participants might guess the nature of the participants before the second condition (DEMAND CHARACTERISTICS)
Name one weakness of repeated measures? (3)
The order of conditions may affect performance (ORDER EFFECTS)
What is they way to get over one condition be easier than the other ?
make tests equivalent
What is the way to get over demand characteristics for repeated measures? (2)
Use a cover story to deceive participants
What is the way to go over order effects for repeated measures ? (3)
use counterbalancing
what is the way to deal with order effects in repeated measures?
counter-balancing
how to counterbalance?
1) Ensure each condition is tested first and second in equal amounts.
2) All ppts split into 2 different groups, one group does completes condition in order of AB the other group complete in BA and ppts scores will be looked at overall.
what is independent measure?
1) Recruit a group of participants
2) Divide them into two
3) One group does the experimental task with the IV set for condition 1
The other group does the experimental task with the IV set for condition 2
3) Measure the DV variable for each group
4) Compare the results for the two group
Name one weakness of independent measures?(1)
no control of ppt variable i.e different abilities or characteristics
Name one weakness of independent measures?(2)
individual differences not taken into account
Name one weakness of independent measure?
will need twice as many participants
what is the way of dealing with ppts having different abilities or characteristics?
randomly allocate ppts to conditions to distribute ppts evenly
what is the way of dealing with ppts individual differences?
use independent measures
how to deal with having twice as many ppts?
have a larger budget
What is matched pairs/participants?
1) recruit a group of people
2) find out what sorts of people you have in the group
3) then recruit another group that matches them for one for one
4) treat the experiment as independent measures
what is one weakness of matched pairs?(1)
very time consuming to match all the ppts on the key variables
what is one weakness of matched pairs? (2)
need a large number of ppts to get matches
what is one weakness of matched pairs?(3)
may not control ALL PPTS variables
ways to deal with the matched pairs being very time consuming?
restrict matching variables (this will reduce the work load)
what is the benefits of randomisation of stimuli?
Improves validity and eliminates investigator effects bias as one set of stimuli might be harder or easier than another and this takes away control from the investigator
How to do the raffle method 1 for randomisation of stimuli?
1) all 30 words in a container
2) Draw out a word for list A then one for list B then back to one for list A
3) Stop when there are 15 words in each list
How to do raffle method 2 for randomisation of stimuli?
1) All 3o words into a container
2)Draw out 15 words for list A
3) Draw out the remaining 15 for list B
