1.1 Scatter plot

A scatter plot is a diagram that displays the values of two variables for a set of data, one point $(X_i, Y_i)$ for each observation. For the advertising data of Example 1.0.1:

XY123451234ASXY1121324254davleesrt(uisninigts()$)
ii — Figure 1: Scatter plot of sales against advertising.

Scatter plots are used to investigate the possible relationship between the variables. Here the points rise from left to right, roughly along a straight line: more advertising goes with more sales.

A scatter plot should always be drawn before any model is fitted. It shows at a glance whether a straight line is sensible at all, and points that do not fit the pattern.

[next] [front] [up]

Questions on this section

Stuck on something here? Ask below and it stays attached to this topic.