a mathematical technique that is used to investigate an association between two variables
correlations strengths
secondary data can be used in the correlation study which makes it less time consuming
correlations limitations
difficult to establish a cause and effect relationship as its only really showing an association and a third variable may be involved that the researcher is unaware of
co-variables
the association between two variables in the correlation study
positive correlation
when one variable increases the other also increases, when the data is presented on scattergram the line of best fit has a positive gradient, has a correlation coefficient more than 0
negative correlation
when one variable increases the other decreases, when the data is presented on a scattergram the line of best fit has a negative gradient, has a correlation coefficient less than 0
zero correlation
no relationship is found between the co-variables, when data is presented on a scattergram, no line of best fit can be drawn as the points on the scattergram are random, it has a correlation coefficient equal to 0
curvilinear relationship
as one variable increases so does the other but only up to a certain point after which as one variable continues to increase the other begins to decrease, forming an inverted U on a graph
