Odds of navigating a random maze

import random

def testMaze(n):
    # there is a doorway connecting cell a,b to cell a,b+1 iff
    # columnConnections[a][b] = 1
    columnConnections = [[0 for x in range(n-1)] for x in range(n)];
    for a in range(0, n):
        for b in range(0, n-1):
            columnConnections[a][b] = random.choice([0,1])
    # there is a doorway connecting cell a,b to cell a+1,b iff
    # rowConnections[a][b] = 1
    rowConnections = [[0 for x in range(n)] for x in range(n-1)];
    for a in range(0, n-1):
        for b in range(0, n):
            rowConnections[a][b] = random.choice([0,1])

    #print columnConnections
    #print rowConnections

    connectivityMatrix = [[0 for x in range(n)] for x in range(n)]
    connectivityMatrix[random.choice(range(n))][random.choice(range(n))] = 1
    #connectivityMatrix[0][0] = 1
    for repeat in range(n*n):
        for x in range(n):
            for y in range(n):
                if connectivityMatrix[x][y] == 1:
                    if y < n-1 and columnConnections[x][y] == 1:
                        connectivityMatrix[x][y+1] = 1;
                    if y > 0 and columnConnections[x][y-1] == 1:
                        connectivityMatrix[x][y-1] = 1;
                    if x < n-1 and rowConnections[x][y] == 1:
                        connectivityMatrix[x+1][y] = 1;
                    if x > 0 and rowConnections[x-1][y] == 1:
                        connectivityMatrix[x-1][y] = 1;
    #print connectivityMatrix

    total = -1;
    for row in connectivityMatrix:
        total = total + sum(row)

    #print total
    #Test if this randomly generated maze is connected.
    return total

total = 0
n = 3
rep = 500
for x in range(rep):
    total = total + testMaze(n)

print total / (rep + 0.0)