All the data analysis in the lab is carried out using discrete numerical methods instead of the continuous analytical model described above. These equations are converted to discrete equations with the time interval 𝑑𝑡 ⇒ ∆𝑡 = 𝑡 2 -𝑡 1 ≡ 1 day, where the subscription 1 and 2 meaning two adjacent days, e.g. 2 is today and 1 is yesterday. Examples are provided in the following for the SIRV model. Equations for the SIR model use the same principle.