solution2.py

# Initialize column sums
column_sums = [0., 0.]

# Iterate over all rows
for row in row_list:
    # For each of the two column values, add to the corresponding sum
    column_sums[0] += row[0]
    column_sums[1] += row[1]

# Calculate the average by dividing by the length
column_avgs = [column_sums[0]/float(len(row_list)),
               column_sums[1]/float(len(row_list))]

print "Column averages: ", column_avgs