title: What do represent arcuate arrows on manifest variable in SEM?
body: <p>i conduct SEM with <code>lavaan</code> and <code>semplot</code> libraries, 
  and i use example for package lavaan (stability of alienation by Wheaton)</p>
  
  <pre><code>lower &lt;-
    '
  11.834,
  6.947,    9.364,
  6.819,    5.091,   12.532,
  4.783,    5.028,    7.495,    9.986,
  -3.839,   -3.889,   -3.841,   -3.625,   9.610,
  -21.899,  -18.831,  -21.748,  -18.775,  35.522,  450.288
  '
  # convert to a full symmetric covariance matrix with names
  wheaton.cov &lt;- getCov(lower, names=c("anomia67","powerless67", "anomia71",
                                       "powerless71","education","sei"))
  # the model
  wheaton.model &lt;-
    '
  # measurement model
  ses     =~ education + sei
  alien67 =~ anomia67 + powerless67
  alien71 =~ anomia71 + powerless71
  # equations
  alien71 ~ alien67 + ses
  alien67 ~ ses
  # correlated residuals
  anomia67 ~~ anomia71
  powerless67 ~~ powerless71'
  
  fit &lt;- sem(wheaton.model, sample.cov=wheaton.cov, sample.nobs=932)
  
  semPaths(fit,whatLables="par",layout = "spring")
  </code></pre>
  
  <p>and i can't understand what do represent accuratearrows on manifest and latent variables.</p>
  
  <p><a href="https://i.stack.imgur.com/WRF9s.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WRF9s.jpg" alt="Screen Arrows"></a></p>