Final answer:
When two variables increase in value together, it indicates a positive correlation, represented by a positive correlation coefficient and generally results in a straight line on a graph.
Step-by-step explanation:
When two variables are correlated and as one increases so does the other, this indicates a positive correlation. This means that there is an association between variables in which a change in one variable is associated with a change in the other variable. Scientists use a statistic known as the correlation coefficient to measure this. The correlation coefficient, represented by the letter r, can range from -1 to +1 and indicates the strength and direction of the relationship.
A positive value of r means that as one variable (x) increases, the other variable (y) tends to increase; similarly, as x decreases, y also tends to decrease. When such data is plotted on a graph, the result typically shows a straight line which represents the direct relationship between the variables.