 The probabilities appearing in (25) can be estimated by dividing event-counts registered in a run of an experiment by the total number of pairs produced. If we assume that the production rate at the source is independent of the analyzer settings, we can take the normalization factor to be the same for each term, and hence, the magnitude of this factor need not be known in order to demonstrate a violation of the upper bound of (25). Another useful observation was made by Eberhard (1993), who demonstrated that the minimal detection efficiency for a detection loophole free experiment can be reduced (from 82% to 67%) for non-maximally entangled states (i.e. a bipartite entangled state with different weight for the two components). This involves starting with a specified efficiency level, and then choosing a state and a set of observables that maximize violation of the CH inequality at that efficiency level.