Correlation Flashcards
positive correlation
two variables tend to change in the same direction
-as the value of x variable increases from one individual to another the Y variable also tends to increase when the X variable decreases the Y variable decreases
negative correlation
two variables tend to go in opposite directions
IE as the Y variable increases, the X variable decreases = is an inverse relationship
Pearson correlation
measures the degree and the direction of the linear relationship between two variables
- it is dimensionalless indie of linear relationship
coefficient of determination
[r-squared ]
~ it measures the proportion of variability in one variable that can be determined for the relationship with the other (ratio of variance)
- can be a percentage of the variability that can be predicted from the relationship with variable X (measure of affect size)
partial correlation
the relationship between two variables while controlling the influence of a third variable by holding it constant
Spearman correlation
can be used for both variables and measured on ordinal scale
- measures consistency (unlike the Pearson’s correlation the relation does not need to be linear for there to be consistency) for which the Spearman correlation is able to identify this consistency// keep in mind that the variables will be consistent because their RANKS are linearly related//
Point biserial correlation
used to measure the relationship between two variables: when one variable consist of regular numerical scores and a second variable has only two values( the second values are normally called, dichotomous variable or a binominal variable
Phi-coefficient
use when both variables are dichotomous.
correlation between the two variables
( notes you need to First convert each of the dichotomous variables to numerical value of 0 or 1 then own with regular Pearson r)
