Description
Our method for determining statistically the members of an open cluster by means of the proper motions (Missana et al., (1990AJ....100.1850M) is amended and its validity is verified by applying it to the cluster IC 4756 with the data given by Herzog et al. (1975A&AS...19..211H), adding nothing to their results. In the computation of the dispersion ellipses of the samples and of the {chi}^2^ for deriving the significance levels, the weights of the proper motions have been taken into account. The results obtained by the criterion of the {chi}^2^ and those obtained by Herzog et al. by the criterion of the maximum likelihood of Sanders (1971A&A....14..226S) are concordant.
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