In a lag plot, data are treated as a time series. In the case of a Lag 1 plot, the observation acquired at time t, U(tk) = U(t), is plotted as a function of the previous observation, U(tk – 1) =U(t – 1).
For white noise, observations are independent and no correlation of U(t) and U(t –
1) is expected. This is the case for the short-circuit data in Figure 1, from which the Lag 1 plot of Figure 3 is constructed.
The Lag 1 plot of the Zener data of Figure 2 is shown in Figure 4.
Summary
In a lag plot, data are treated as a time series. In the case of a Lag 1 plot, the observation acquired at time t, U(tk) = U(t), is plotted as a function of the previous observation, 
