\(M_{i}\) – Molar mass of the chain
\(n_{i}\) – Number of molecules with mass \(M_{i}\)
Another important property is the dispersity that indicates the relationship between \(M_{n}\) and \(M_{w}\). The more varied the sizes of the molecules, the greater is the dispersity value (which is always greater than 1). In the other hand, when chain sizes are close, the polydispersity is approximately 1.