Beta_hat                Estimate fixed effects by nonlinear least
                        squares
Dhypothesis_test        Permutation test for random effects in linear
                        and nonlinear mixed-effects models
Dmethod                 Non-parametric approach to estimate variance
                        components in a linear and nonlinear
                        mixed-effects model
MM_base                 Compute first-stage quantities for MM and MMF
                        estimators
SkillAcq                Skill acquisition data
Tstat                   Compute the observed test statistic
ZandYPred               Compute Jacobian matrix and fixed-effects
                        predicted values
bootstrap_se            Bootstrap standard errors for variance
                        component estimates
plot.Dmethod            Plot method for 'Dmethod' objects
plot.Dtest              Plot method for 'Dtest' objects
plot_condition          Plot per-subject condition numbers
plot_fitted             Plot fitted curves overlaid on observed data
plot_perm_hist          Histogram of the permutation null distribution
plot_profiles           Plot raw individual trajectories
plot_residuals          Plot residuals versus fitted values
plot_variance           Compare variance component estimates across
                        methods
