What is the graphing method used to illustrate the relationship between two quantitative variables?

A bar graph for any type of quantitative data is called a histogram. The discrete values taken by the data are labeled in ascending order across the horizontal axis, and a rectangle is drawn vertically so that the height of each rectangle corresponds to each discrete variable's frequency or relative frequency.

A scatterplot is the most useful display technique for comparing two quantitative variables. We plot on the y-axis the variable we consider the response variable and on the x-axis we place the explanatory or predictor variable.

The best way to determine how two variables relate to each other is by plotting the data points on a scatter plot, a graph where each data point is plotted individually. If all the points seem to follow a line of some sort, then we can interpret that relationship.