Though beta always involves the measurement of variance and covariance over a period, there is no universal, agreed-upon length of that period.

We present in this paper general formulas for deriving the maximum likelihood estimates and the asymptotic variance-covariance matrix of the positions and effects of quantitative trait loci (QTLs) in ...

Alternatively, you can directly specify the matrix A to find the D-optimal design when A is the variance-covariance matrix for the runs. You can specify the data set containing the covariance matrix ...

ANOVA of unweighted means can be used to estimate variance components easily. In the multivariate normal case, the variance-covariance matrix of the estimators can be computed by a simple modification ...

The COV= option must be specified to compute an approximate covariance matrix for the parameter estimates under asymptotic theory for least-squares, maximum-likelihood, or Bayesian estimation, with or ...