Correlations 📈 Flashcards
What is a correlational technique?
Correlational techniques are non-experimental methods used to measure how strong the relationship is between two (or more) variables.
— In an experiment, the effect of an independent variable upon the dependant variable is measured; however, in correlational studies the movement and direction of co-variables in response to each other is measured.
— There is no claim of a cause and effect relationship, although after a correlational study has been conducted, further research will often be conducted to determine if one variable is, in fact, affecting the other.
What are the different types of correlation?
> Positive correlation - As one variable increases, the other variable increases (eg. height and shoe size).
Negative correlation - As one variable increases, the other variable decreases (eg. GCSE grades and the amount of times the are absent from school).
Zero correlation - Occurs when a correlational study finds no relationship between variables (eg. the amount of rainfall in Wales and the number of people who read Lord of the Flies).
What is a correlation coefficient?
A correlation coefficient is used to measure the strength and nature (positive or negative) of the relationship between two co-variables. The correlation coefficient number represent the strength of the relationship and can range between -1.0 and +1.0.
The nearer the number is to +1 or -1, the stronger the correlation. A perfect positive correlation coefficient of +1.0 and for a perfect negative correlation is -1.
What is a scattergram?
A scattergram (sometimes called a scattergraph) is a graph that shows the correlation between two sets of data (co-variables) by plotting points to represent each pair of scores.
— It indicates the degree and direction of the correlation between the co-variables, one of which is indicated on the X-axis and the other on the Y-axis.
EVALUATION: Correlational Techniques
STRENGTH - PRELIMINARY RESEARCH INVESTIGATIONS
P: Correlational studies are an ideal place to begin preliminary research investigations. Since they measure the strength of a relationship between two (or more) variables, this can provide valuable insight for future research.
E: This type of analysis can be used when a labolatory experiment would be unethical as the variables are not manipulated, merely correlated.
E: In addition, secondary data can also be used in correlational studies which alleviates the concern over informed consent as the information is already in the public domain eg. government reports.
LIMITATION - CAUSE AND EFFECT
P: There are limitations with using the correlational method. It is not possible to establish a cause and effect relationship through correlation co-variables.
E: This means a researcher cannot conclude that one variable caused the other variable to increase/ decrease as there could be other factors which influenced the relationship - referred to as the third variable problem.
E: Moreover, correlations only identify linear relationships and not curvilinear. For example, the relationship between temperature and aggression is curvilinear, that is the relationship is positive to a point; however, at very high temperatures, aggression declines.
