Final answer:
Option a, where X has a positive charge and Y has a negative charge, is true for objects that attract each other, consistent with the principles of electrostatic attraction. The variables have a strong negative linear relationship, suitable for linear regression analysis.
Step-by-step explanation:
According to the given information about the relationship between variables X and Y, if objects X and Y attract each other and the relationship is represented on a graph with perpendicular axes, where the x-axis is the independent variable and the y-axis is the dependent variable, the attraction between them would imply opposite charges. Therefore, option a, X has positive charge and Y has negative charge, is true for objects that attract each other. Options b (X has negative charge and Y has positive charge), c (X and Y both have positive charge), and d (X is neutral and Y has a charge) describe other scenarios that do not necessarily match the phenomenon of electrostatic attraction.
We can also discuss the linear relationship between two variables on a graph, which is represented by the equation y = mx + b. The slope, m, indicates the relationship's direction and strength. A strong negative linear relationship suggests that as one variable increases, the other decreases, which could be analyzed effectively using linear regression.