Psychology: A Scientific Discipline — Psychology STD 12 Commerce / Arts — Question

A correlation refers to a statistical tool used to measure the relationship between two or more variables. If the change in one variable is accompanied by a change in the other variable, this interdependence is called correlation. It is measured by correlation coefficient which extends between -1.00 to +1.00. Direction of correlation can be positive or negative.
The types of correlation are:

1. Positive – Both variables move in the same direction i.e., both increase or both decrease. It extends 0.00 to +1.00 for e.g., identical twins reared together showed IQ correlation of +.88.
2. Negative – Variables move in the opposite direction i.e., increase in one variable is associated with a decrease in the other variable. The value of negative correlation is 0.00 to -1.00 for e.g., high level of job satisfaction and low level of absenteeism.
3. Zero – Any change in one variable brings about no significant change in the other variable. Value of coefficient is 0 for e.g., height and intelligence.