Psychologists measure many concepts that appear to contain more information than an ordinal scale, but it is difficult to prove that the intervals between the numbers are equal. As a result, variables such as depression, intelligence, happiness, and sociability are usually treated as if they were interval scale variables. The dependent variable is the one being tested and measured in an experiment, and it is “dependent” on the independent variable. For instance, symptoms of depression depend on the type of therapy used.
A study showed that loneliness can predict increases in depressive symptoms independently of other factors such as stress, social support, and negativity. The question of structure is whether depression occurs in a discrete type or a continuum. The statistical relationship between psychotherapy and the number of depressive symptoms reflects the fact that psychotherapy (the independent variable) causes a reduction in symptoms (the dependent variable).
