RM - Correlations Flashcards
What is a correlation?
Mathematical technique in which a researcher investigates an association between 2 variables - co-variables.
What are co-variables?
Variables investigated within a correlation (e.g. height and weight). Not referred to as IV and DV because correlation looks for an association between variables not cause and effect.
What is a positive correlation?
As one co-variable increases so does the other. E.g. no. of ppl in a room and amount of noise tend to positively correlate.
What are negative correlations?
As one co-variable increases the other decreases. E.g. no. of ppl in a room and amount of personal space tend to be negatively correlated.
What is a zero correlation?
When there is no relationship between 2 co-variables.
E.g. No. of ppl in a room in Manchester and total daily rainfall in Peru has zero correlation.
How are correlations shown?
They are plotted on a scattergram.
1 co-variable on the x-axis and the other on the y-axis. Each point on the graph is the x and y position of each variable.
What is the difference between correlations and experiments?
Experiments try to determine cause and effect by manipulating the IV to see the effect on the DV.
In a correlation there is no manipulation of variables so it is not possible to establish cause and effect.
E.g. strong positive correlation between caffeine and anxiety, we cannot assume caffeine causes anxiety.
Strengths: Why are correlations useful?
Useful preliminary tool for research. By assessing strength and direction of relationship they provide a precise and quantifiable measure of how 2 variables are related.
May suggest ideas for possible future research. Often a starting pnt to assess possible patterns between variables before researchers commit to a study.
Strengths: Why are they quick and economical?
Quick and economical to carry out. No need for a controlled environment and no manipulation of variables. Can use data collected by others so they are less time consuming than experiments.
Weaknesses: Cause and effect
Due to the lack of manipulation of variables, they can tell us how variables are related but not why. Cannot demonstrate cause and effect so we dk which variable is causing change to the other.
Weaknesses: Intervening variables
Another untested variable is causing the relationship between the 2 co-variables - intervening variable. It remains unaccounted for.
Weaknesses: Misuse or misinterpretation
Relationships could be presented as casual facts when they are not, especially in media.
E.g. relationship between being raised in a single parent family and increased likelihood of committing crime. This does not mean that single parent families cause crime or the children will inevitably go out and commit crime. There may be several intervening variables such as emotional distress when parents split up.
What is a correlation coefficient?
A number between -1 and +1 that represents the direction and strength of a relationship between co-variables.
What does +1 mean?
A perfect positive correlation.
What does -1 mean?
A perfect negative correlation.
