Fig. 4

Stochastic variations in diffusion limit the accuracy of D measurements. a In case of low positional uncertainty (σ= 10 nm), the best number of fitting points is 2, for different values of D. b In case of higher positional uncertainty (σ = 200 nm), errors in position detection dominate the error in D for small displacements, and the best number of MSD points increases (see inset). Each point in the plot is the average ρ obtained from 100 simulations of 200 points traces