values_list = []

for row in b:
   values_list.append(row[1])

1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
0,1,2,3,4
2,3,4,5,6

#!/bin/env python

col = 2

values = []
with open('csv.csv', 'r') as csv:
    for line in csv.readlines():
        elements = line.strip().split(',')
        values.append(int(elements[col]))

csum = sum(values)
cavg = sum(values)/len(values)
print("Sum of column %d: %f" % (col, csum))
print("Avg of column %d: %f" % (col, cavg))

$ python parsecsv.py
Sum of column 0: 6.000000
Avg of column 0: 1.000000

$ python parsecsv.py
Sum of column 2: 18.000000
Avg of column 2: 3.000000