def getAveIncome(cluster):
    """
    Given a Cluster object, finds the average income field over the members
    of that cluster.
    
    cluster: the Cluster object to check
    
    Returns: a float representing the computed average income value
    """
    tot = 0.0
    numElems = 0
    for c in cluster.getPoints():
        tot += c.getOriginalAttrs()[1]

    return float(tot) / len(cluster.getPoints())