Question

what must be present in order to say that a correlation exists?
a. an opinion that things are the same
b. a relationship between variables
c. a desire for change
d. a wish to identify cause and effect

Explanation:

Correlation refers to a statistical relationship between two or more variables. It measures how one variable changes in relation to another. An opinion (A) is subjective and not a basis for establishing a correlation. A desire for change (C) is an emotional or motivational aspect, not relevant to the statistical concept of correlation. While correlation can sometimes be a step towards exploring cause - effect (D), the fundamental requirement for a correlation is just a relationship between variables.

Answer:

B. A relationship between variables