  To estimate the strength of the Bose-Einstein correlations and the radius of
the hadronization region in multiparticle production, the two-particle
correlation functions $R$ for identical pairs is adjusted to a parametric
function describing the enhancement at small momentum differences. This is
usually done by means of a binned uncorrelated least squares fit. This article
demonstrates that this procedure underestimates the statistical errors. A
recipe is given to construct from the data the covariance matrix To estimate
the strength of the Bose-Einstein correlations and the radius of the
hadronization region in multiparticle production, the two-particle correlation
functions $R$ for identical pairs is adjusted to a parametric function
describing the enhancement at small momentum differences. This is usually done
by means of a binned uncorrelated least squares fit. This article demonstrates
that this procedure underestimates the statistical errors. A recipe is given to
construct from the data the covariance matrix between the bins of the histogram
of the two-particle correlation function.
