Hi
I don't have Access to the previous model just now, but provide you With the results from another mix MNL model With lognormal cost parameter, use of deltaMethod to check for significance of estimated cost parameter.
This is all output from that model, including the vcoc. As you can see, a very significant cost parameter according to the p-value, but strange outputs for estimate and std.error (only 0).
Model run using Apollo for R, version 0.1.0
www.ApolloChoiceModelling.com
Model name : MMNL_data_gruve
Model description : MMNL model with fixed cost attr
Model run at : 2020-09-08 14:23:26
Estimation method : bfgs
Model diagnosis : successful convergence
Number of individuals : 1123
Number of observations : 8546
Number of cores used : 3
Number of inter-person draws : 100 (halton)
LL(start) : -102324
LL(0) : -9388.741
LL(final) : -7268.239
Rho-square (0) : 0.2259
Adj.Rho-square (0) : 0.2249
AIC : 14554.48
BIC : 14617.96
Estimated parameters : 9
Time taken (hh:mm:ss) : 00:06:54.14
Iterations : 64
Min abs eigenvalue of hessian : 0.562111
Some eigenvalues of hessian are positive, indicating potential problems!
Estimates:
Estimate Std.err. t.ratio(0) Rob.std.err. Rob.t.ratio(0)
asc -2.2083 0.0862 -25.60 0.0946 -23.36
seabed_mu 0.1034 0.0083 12.49 0.0117 8.81
seabed_sig 0.1648 0.0098 16.76 0.0163 10.13
salmon_mu -0.0104 0.0092 -1.12 0.0095 -1.10
salmon_sig 0.1539 0.0144 10.69 0.0218 7.07
jobs_mu 0.0075 0.0018 4.21 0.0019 3.89
jobs_sig 0.0219 0.0033 6.67 0.0044 5.03
cost_mu -12.1086 0.0080 -1511.39 0.0108 -1122.73
cost_sig 0.5983 NaN NaN 0.0061 98.75
Overview of choices for model component "MNL"
alt1 alt2 alt3
Times available 8546.00 8546.00 8546.00
Times chosen 2537.00 3169.00 2840.00
Percentage chosen overall 29.69 37.08 33.23
Percentage chosen when available 29.69 37.08 33.23
> apollo_saveOutput(model)
Estimates saved to MMNL_data_gruve_estimates.csv
Classical covariance matrix saved to MMNL_data_gruve_covar.csv
Robust covariance matrix saved to MMNL_data_gruve_robcovar.csv
Classical correlation matrix saved to MMNL_data_gruve_covar.csv
Robust correlation matrix saved to MMNL_data_gruve_robcorr.csv
Model object saved to MMNL_data_gruve.rds
>
> # ################################################################# #
> ##### POST-PROCESSING ####
> # ################################################################# #
>
> ### Print outputs of additional diagnostics to new output file (remember to close file writing when complete)
> sink(paste(model$apollo_control$modelName,"_additional_output.txt",sep=""),split=TRUE)
> deltaMethod_settings <- list(operation="lognormal", parName1="cost_mu", parName2="cost_sig")
> apollo_deltaMethod(model, deltaMethod_settings)
Running Delta method computations
Value Robust s.e. Rob t-ratio (0)
Mean for exp(N( cost_mu , cost_sig ) 0 0 108.41
SD for exp(N( cost_mu , cost_sig ) 0 0 76.67
> vcov(model)
asc seabed_mu seabed_sig salmon_mu
asc 7.438793e-03 -2.157429e-04 -2.001317e-04 -1.926618e-04
seabed_mu -2.157429e-04 6.854278e-05 5.289119e-05 -2.314408e-05
seabed_sig -2.001317e-04 5.289119e-05 9.667019e-05 -3.488203e-05
salmon_mu -1.926618e-04 -2.314408e-05 -3.488203e-05 8.538430e-05
salmon_sig -2.797337e-05 -5.517701e-05 -8.196384e-05 6.516198e-05
jobs_mu -4.120852e-05 -3.767929e-06 -4.629812e-06 -7.073551e-07
jobs_sig -1.826342e-05 -9.308441e-06 -1.497270e-05 3.115459e-06
cost_mu 2.569514e-04 -6.477486e-05 -4.826137e-05 2.385143e-05
cost_sig 5.947195e-05 1.307637e-05 1.960251e-05 -2.408104e-06
salmon_sig jobs_mu jobs_sig cost_mu
asc -2.797337e-05 -4.120852e-05 -1.826342e-05 2.569514e-04
seabed_mu -5.517701e-05 -3.767929e-06 -9.308441e-06 -6.477486e-05
seabed_sig -8.196384e-05 -4.629812e-06 -1.497270e-05 -4.826137e-05
salmon_mu 6.516198e-05 -7.073551e-07 3.115459e-06 2.385143e-05
salmon_sig 2.072066e-04 3.320100e-06 1.014155e-05 5.185691e-05
jobs_mu 3.320100e-06 3.178285e-06 2.853481e-06 5.896439e-07
jobs_sig 1.014155e-05 2.853481e-06 1.082481e-05 6.454960e-06
cost_mu 5.185691e-05 5.896439e-07 6.454960e-06 6.418521e-05
cost_sig -1.346165e-05 -6.031766e-06 -1.367829e-05 1.099505e+00
cost_sig
asc 5.947195e-05
seabed_mu 1.307637e-05
seabed_sig 1.960251e-05
salmon_mu -2.408104e-06
salmon_sig -1.346165e-05
jobs_mu -6.031766e-06
jobs_sig -1.367829e-05
cost_mu 1.099505e+00
cost_sig -1.099492e+00
>