Helper function to calculate the standard errors of standard deviations and correlations from a MIXL model. Together, all the helper functions and the four functions fn_se_var, fn_se_cov, fn_se_corr and fn_se_std, is an application of the Delta method. The helper functions are for internal use only and are not exported.

fn_1(a, L)



An integer indicating the row position of the random parameter in the asymptotic variance-covariance matrix


The lower cholesky matrix

References Daly, A. J., Hess, S., & de Jong, G., 2012, Calculating errors for measures derived from choice modelling estimates, Transportation Research Part B, 46(2):333-341