Repeated Measures Design and Correlations Flashcards
What is a repeated measures design?
Participants are tested in 2 conditions (or more)
What are the advantages of repeated measures designs?
> Fewer participants are needed to run an experiment as compared to a between-groups design
This can save material, money and effort
Less error in your experiment than there would be if you had 2 separate groups
Disadvantage of repeated measures designs?
Practice/ Order effects
what factors can practice effects occur due to?
A number of different factors e.g. learning, fatigue, adaptation, habituation, sensitisation, contrast etc.
How do we combat practice/order effects?
COUNTERBALANCING
What is counterbalancing?
This means assigning participants to different conditions in different orders.
What is complete counterbalancing?
Takes into account every possible combination e.g. 123, 231, 312.
when does complete counterbalancing become more difficult?
when you have lots of different conditions- lots of different combinations.
What is partial counterbalancing?
randomly aelecting a sub set of possible conditions orders and assigning participants randomly to those.
One type of ______ design is called a correlational design.
Repeated measures
How many variables will a correlational design have?
2
What scales can variables be on in a correlational design?
either ordinal, interval or ratio.
What study design is this?
Increasing self harm is associated with lower self esteem.
Correlational design
A correlation is a description about how…
2 variable are associated with one another
name the 2 types of correlation.
Positive and Negative.
name this correlation type:
As one variable increases so does the other.
Positive :)
name this correlation type:
As one variable increases, the other decreases.
negative.
What is the descriptive statistic for a correlation?
A scatterplot :)
If you have an IV and a DV, what axis should the IV be on in a scatter plot?
The x-axis.
what can we draw to help us see a potentially significant trend on the scatter plot?
A line of best fit
What can the line of best fit show us?
A potentially sig relationship between 2 variables.
Also helps identifying outliers.
If correlation = 0 what does this mean?
There’s no correlation.
If correlation = -1 what does this mean?
Strong negative correlation
If correlation = +1 what does this mean?
Strong positive correlation
the stronger the correlation, the ____ the dots to the line of best fit.
closer
what does r stand for?
correlation :)
what is the strongest correlation you can get?
r= 1
OR
r = -1