机器算法验证 - 如何解释这个熔岩结构方程模型？ - 吾爱随笔录

我使用 R 中的 lavaan 包从 iris 数据集中创建了以下结构方程模型：

在此处输入图像描述

我如何解释这些数字。输出（lavaan 包的 sem() 函数）如下所示。它没有给出任何 P 值：

lavaan (0.5-18) converged normally after  64 iterations

  Number of observations                           150

  Estimator                                         ML
  Minimum Function Test Statistic                   NA
  Degrees of freedom                                -4
  Minimum Function Value               0.0000000000000

Parameter estimates:

  Information                                 Expected
  Standard Errors                             Standard

                   Estimate  Std.err  Z-value  P(>|z|)
Latent variables:
  sepf =~
    Sepal.Length      1.000
    Sepal.Width      -0.469
  petf =~
    Petal.Length      1.000
    Petal.Width       0.507
  lenf =~
    Petal.Length      1.000
    Sepal.Length     -0.177
  widf =~
    Sepal.Width       1.000
  strf =~
    sepf              1.000
    petf              2.084
  bulkf =~
    lenf              1.000
    widf              0.579

Regressions:
  strf ~
    Species           0.842
  bulkf ~
    Species           0.290

Covariances:
  strf ~~
    bulkf             0.065

Variances:
    Sepal.Length      0.361
    Sepal.Width       0.129
    Petal.Length      0.231
    Petal.Width       0.047
    sepf             -0.120
    petf             -0.220
    lenf             -0.179
    widf              0.084
    strf              0.053
    bulkf            -0.025
-----------------------------------------------
Warning messages:
1: In lav_data_full(data = data, group = group, group.label = group.label,  :
  lavaan WARNING: unordered factor(s) with more than 2 levels detected in data: Species
2: In lav_model_vcov(lavmodel = lavmodel, lavsamplestats = lavsamplestats,  :
  lavaan WARNING: could not compute standard errors!
  lavaan NOTE: this may be a symptom that the model is not identified.

3: In lavaan::lavaan(model = model, data = mydf, model.type = "sem",  :
  lavaan WARNING: some estimated variances are negative
4: In lavaan::lavaan(model = model, data = mydf, model.type = "sem",  :
  lavaan WARNING: covariance matrix of latent variables is not positive definite; use inspect(fit,"cov.lv") to investigate.
5: In sqrt(ETA2) : NaNs produced
6: In sqrt(ETA2) : NaNs produced
7: In sqrt(ETA2) : NaNs produced
>

我只是将大估计视为重要吗？感谢您的洞察力。