Figure 19. Koch’s predictions on the negative correlation between mother and daughter generation times.

(A) The coefficient-of-variation ( $=\sqrt{\text{mean}/\text{variance}}$, CV) of generation time is larger than the CV of division length. (B) Based on (A) and his explanation why the duration of parts of the same cell cycle must be negatively correlated, Koch deduced that the generation time correlation between mother and daughter should be negative, whereas that of two daughters must be positive.