To complete the sentence, the correct answer is "two sets of values." Scatter plots are graphical representations used to observe and analyze the relationship or trend between two variables, typically represented by two sets of values. In a scatter plot, each data point is plotted as a dot on the graph, with one variable's values represented on the x-axis and the other variable's values represented on the y-axis. By examining the pattern or trend formed by these plotted points, we can determine if there is a strong positive association (as one variable increases, the other variable also increases), a strong negative association (as one variable increases, the other variable decreases), or no significant association between the two variables.