Final answer:
The variable listed at the bottom of a scatterplot, on the horizontal axis, is known as the explanatory or independent variable. It is believed to influence the response or dependent variable, which is plotted on the vertical axis.
Step-by-step explanation:
The variable listed at the bottom of a scatterplot on the horizontal axis is the explanatory variable. This variable, also known as the independent variable, is the one that you believe might influence the other variable. For example, if you were looking at the relationship between study time and test scores, study time would typically be on the horizontal axis as the explanatory variable, and test scores would be on the vertical axis as the response variable or dependent variable.
When conducting an experimental study, the explanatory variable is often the condition that researchers manipulate. For example, when analyzing the effect of the size of tableware on the amount of food eaten, the size of the tableware would be the explanatory variable. Similarly, when evaluating whether there is a relationship between ranking of a state and the area of the state, the state ranking would be considered as the explanatory variable.