One of the things we'd like able to do is to compute statistics on lists.
Imagine that we've got a set of n nodes and we've got L, which is a list of values--
one for each of the nodes in the network and we want to compute statistics.
What are statistics? Astatistic is actually quite a simple idea.
It's just a number that summarizes a list of numbers.
If we have a list L--say a list of the centrality scores.
There's lots of different statistics that we can imagine that would summarized
these list of numbers--for example, how many numbers are in the list.
What's the largest number in the list? What's the total of all the scores in the list?
How many scores are in the list that are between 2 and 3 inclusive?
These are all different statistics and some of these are may be more useful than others
but there's lots of different statistics that we might want to compute.
In general when you're doing an analysis of large structures like social networks,
we need some way of summarizing this large amount of data--you can't just present the data
in the raw form--it's too much for people to think of all at once.
Statistics and computing statistics ends up being a really important operation.