title: Plotting multiple polynomial and linear regression lines on the same scatter plot
body: <p>I've got a problem with the following regression models. I want to get two polynomial regression lines and one linear regression line on the same scatter plot. In addition, i want to show the equations for the three different models on the same graph using ggpmisc package. </p>
  
  <p>I've coded my problem as follows: </p>
  
  <pre><code>equation &lt;- y ~ x
  
  df %&gt;%
    filter(Year == 2010) %&gt;%
    ggplot(aes(x = commutetime, y = carcommute, color=Fabric, shape = Fabric)) +
    geom_point() +
    theme_minimal()+
    geom_point(size = 3.5, aes(color = Fabric, shape = Fabric))+
    stat_smooth(method = "lm", formula = y ~ poly(x, 2), size = 1, se = FALSE)+
    scale_color_manual(values = c("#00AFBB", "#E7B800", "#FC4E07"))+
    scale_fill_manual(values = c("#00AFBB", "#E7B800", "#FC4E07"))+
    stat_poly_eq(aes(label = paste(..eq.label.., ..rr.label.., sep = "~~~")), 
                 label.x.npc = "center", label.y.npc = 0.39,
                 formula = equation, parse = TRUE, size = 5)
  </code></pre>
  
  <p>But i am getting the following graph: Automobile and Walking fabrics should reflect the quadratic regression while Transit should show decreasing trend as commute time increases. That means i want transit to be straight line and keep the quadratic regression for both automobile and walking. Any idea of how i can modify my code to show that. </p>
  
  <p>Similarly my equations for the three models overlap? How can i solve this? Thank you very much in advance!!! </p>
  
  <p>Here's  my data:</p>
  
  <pre><code>      carcommute commutetime  Fabric
  3         35.9        41.6    Walking
  4         84.0        34.9    Walking
  7         28.3        37.1    Transit
  8         82.6        31.4    Transit
  11        23.3        35.1    Walking
  12        63.0        30.3    Walking
  15        34.2        36.4    Walking
  16        80.7        29.3    Walking
  19        31.1        36.8    Walking
  20        76.1        33.1    Walking
  23        29.9        37.8    Walking
  24        78.4        33.2    Walking
  27        32.2        39.5    Walking
  28        79.8        35.2    Walking
  31        31.7        42.7    Walking
  32        82.9        38.6    Walking
  35        34.1        43.1    Walking
  36        79.7        37.6    Walking
  39        28.5        45.1    Walking
  40        76.3        39.3    Walking
  43        32.2        47.1    Walking
  44        81.9        38.5    Walking
  47        36.6        47.6    Walking
  48        85.5        41.3    Walking
  51        34.4        43.3    Walking
  52        83.3        38.6    Walking
  55        36.7        40.3    Walking
  56        91.0        35.4    Walking
  59        33.8        39.2    Walking
  60        82.5        31.4    Walking
  63        47.0        43.3    Walking
  64        89.9        36.8    Walking
  67        41.1        43.5    Walking
  68        87.8        39.1    Walking
  71        33.6        43.8    Walking
  72        90.4        35.7    Walking
  75        38.9        42.7    Walking
  76        86.7        36.4    Walking
  79        32.1        39.3    Walking
  80        84.4        31.9    Walking
  83        32.2        42.2    Walking
  84        88.7        35.3    Walking
  87        32.9        44.0    Walking
  88        87.5        36.4    Walking
  91        41.2        38.2    Transit
  92        89.1        31.5    Transit
  95        42.6        39.5    Walking
  96        87.6        30.3    Walking
  99        42.2        39.4    Walking
  100       84.2        33.5    Walking
  103       40.2        42.1    Walking
  104       88.5        31.0    Walking
  107       59.9        41.1 Automobile
  108       76.9        35.9 Automobile
  111       59.4        32.7 Automobile
  112       75.8        32.5 Automobile
  115       57.0        38.1    Walking
  116       67.1        35.8    Transit
  119       56.9        39.7    Walking
  120       76.2        33.0    Walking
  123       67.9        37.5    Transit
  124       78.7        36.0    Transit
  127       60.7        41.1    Transit
  128       75.2        38.6    Transit
  131       50.6        43.7    Walking
  132       81.5        37.9    Walking
  135       61.0        45.5    Transit
  136       76.5        38.8    Transit
  139       67.2        42.0    Transit
  140       83.5        36.8    Transit
  143       60.7        22.4 Automobile
  144       49.7        17.5 Automobile
  147       70.4        44.3 Automobile
  148       87.4        22.7 Automobile
  151       61.6        39.4 Automobile
  152       80.1        41.4 Automobile
  155       62.7        39.9    Transit
  156       79.6        42.1    Transit
  175       50.4        41.9    Transit
  176       67.0        44.7    Transit
  191       50.1        45.3    Transit
  192       83.1        43.8    Transit
  195       51.0        43.1    Walking
  196       75.1        43.4    Walking
  207       52.1        40.3    Walking
  208       78.3        47.3    Walking
  223       46.0        42.7    Transit
  224       77.7        45.9    Transit
  227       74.0        29.0 Automobile
  228       80.7        29.7 Automobile
  231       62.4        34.4 Automobile
  232       88.1        45.9 Automobile
  235       66.4        38.3    Transit
  236       81.6        44.0    Transit
  247       59.8        42.7    Transit
  248       81.5        49.2    Transit
  267       52.4        41.9 Automobile
  268       83.6        46.6 Automobile
  271       55.0        40.9    Transit
  272       80.5        42.8    Transit
  275       61.5        44.1 Automobile
  276       82.3        40.7 Automobile
  279       73.5        33.7    Transit
  280       89.5        35.8    Transit
  283       74.0        36.0 Automobile
  284       81.8        42.0 Automobile
  287       50.6        41.9    Transit
  288       79.0        50.1    Transit
  291       60.5        41.8 Automobile
  292       82.8        46.2 Automobile
  295       55.3        41.3 Automobile
  296       77.8        43.0 Automobile
  299       68.7        43.7 Automobile
  300       82.1        44.2 Automobile
  315       69.9        36.9 Automobile
  316       86.6        40.1 Automobile
  319       78.9        25.9 Automobile
  320       73.9        30.1 Automobile
  323       76.8        25.5 Automobile
  324       76.3        29.1 Automobile
  327       72.0        39.2 Automobile
  328       86.4        45.7 Automobile
  331       74.1        35.9 Automobile
  332       86.3        33.8 Automobile
  335       74.6        33.9 Automobile
  336       78.6        40.4 Automobile
  339       65.0        39.4 Automobile
  340       90.5        39.6 Automobile
  343       73.2        31.2 Automobile
  344       79.0        30.7 Automobile
  351       73.6        29.9 Automobile
  352       63.0        27.3 Automobile
  355       74.7        20.1 Automobile
  356       72.7        31.9 Automobile
  359       77.4        26.1 Automobile
  360       79.2        29.4 Automobile
  </code></pre>
  
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