What is $Var(S_i)$?

In [2]:

    

import urllib2
import csv
import numpy

url = ('https://raw.githubusercontent.com/Upward-Spiral-Science'
       '/data/master/syn-density/output.csv')
data = urllib2.urlopen(url)
fieldnames = ['x', 'y', 'z', 'unmasked', 'synapses']
reader = csv.reader(data)
reader.next()

rows = [[int(col) for col in row] for row in reader]
mean_si = (1. * sum([row[-1] for row in rows])) / len(rows)


    

In [3]:

    

numpy.var([row[-1] for row in rows])


    

    
Out[3]:





8463.553588148694