Final answer:
The statement is false because while a correlation coefficient of +1 does indicate a perfect positive linear relationship, where variables move in the same direction, it does not prove that one variable causes the change in the other variable.
Step-by-step explanation:
If the correlation coefficient between two variables is +1, it means that there is a perfect positive linear relationship between the variables. This means that if one variable increases, the other variable also increases, and if one variable decreases, the other decreases correspondingly.
However, it is important to note that correlation does not imply causation. A correlation coefficient of +1 does not prove that a change in one variable causes a change in the other variable; it only indicates that they change together in a linear relationship. For example, two variables x and y that have a correlation coefficient of +1 will increase and decrease in unison, but one does not necessarily cause the change in the other.
Therefore, the statement that 'an increase in one variable causes the other variable to increase' when the correlation coefficient is +1 is False.