Linear relationships

Generally speaking two variables can related in three difference “fashions”: linear, non-linear, or non-related. There are different mathematical approaches to tackle each type of relationship. Here we will cover only linear relationships, but I want you to learn to at least identify the other types.

Let’s start with the linear relationships. Linear relationships, as the name sort of indicates are better described by a straight line. This type of relationships can be further separated between positive relationships, in which Y-increases as X-increases and negative relationships, in which Y-decreases as X-increases.

Obviously, you also have the option that the two variables do not relate to each other (see figure below)

Figure 6.1: Types of relationships