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Chapter 5. Growth Dynamics
Figure 5.4: Correlation coefficient distributions across all systems
and releases. The top graph shows the box-plots for each of the 10
metrics under analysis. The bottom graph plots the distribution for
the metrics.
any substantial trend, it is an indication that there is a preference by
developers towards a certain shape profile and the process of evolution
does not have any impact of the underlying distribution.
In order to identify if there was a sufficiently strong trend, we compute
the Spearman’s rank correlation coefficient ρ [279] between Gini Coefficient
values (for each metric) over Age (measured in days since birth)
for each system in our data set. We applied the t-test to ensure that
the reported Spearman correlation coefficient values were significantly
different from zero.
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