Final answer:
The relationship between two variables when one changes can be either in the same direction (positive correlation) or opposite (negative correlation), which is indicated by the correlation coefficient. However, without further details about the relationship's nature (positive or negative), it's impossible to determine the specific behavior of the second variable's scores.
Step-by-step explanation:
When saying two variables are correlated, it indicates that there is a relationship between their movements. If the correlation is positive, changes in one variable will be mirrored by changes in the same direction of the other variable. Conversely, a negative correlation signals that changes in one variable will result in changes in the opposite direction of the other variable.
A correlation coefficient provides more details about the relationship by indicating its strength and direction. A coefficient close to +1 or -1 shows a strong relationship, where changes in one variable are highly predictable based on changes in the other variable.
Given this, the correct completion for the statement is, 'If two variables are related, then as scores vary in one direction around the mean of one variable, the scores in the other variable should cannot be determined without knowing more about the nature of their relationship.'