  The data we analyze derives from the observation of numerous cells of the
bacterium Escherichia coli (E. coli) growing and dividing. Single cells grow
and divide to give birth to two daughter cells, that in turn grow and divide.
Thus, a colony of cells from a single ancestor is structured as a binary
genealogical tree. At each node the measured data is the growth rate of the
bacterium. In this paper, we study two different data sets. One set corresponds
to small complete trees, whereas the other one corresponds to long specific
sub-trees. Our aim is to compare both sets. This paper is accessible to post
graduate students and readers with advanced knowledge in statistics.
