README.md

Linear Regression R^2

Final Result

CustomChart {
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      type: "dimension"
      label: "First Quantitative Variable"
    },

    field b {
      type: "dimension"
      label: "Second Quantitative Variable"
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  options {
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    option num_type {
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      type: "select"
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    option cat_type {
      label: "Type of Qualitative Variable"
      type: "select"
      options: ["nominal", "ordinal"]
      default_value: "nominal"
    }
  }
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    "data": {
      "values": @{values}
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        "mark": {
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            "type": "quantitative"
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          "y": {
            "field": @{fields.b.name},
            "type": "quantitative"
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      },
      {
        "mark": {
          "type": "line",
          "color": "firebrick"
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            "regression": @{fields.b.name},
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            "type": "quantitative"
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          "y": {
            "field": @{fields.b.name},
            "type": "quantitative"
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        }
      },
      {
        "transform": [
          {
            "regression": @{fields.b.name},
            "on": @{fields.a.name},
            "params": true
          },
          {"calculate": "'R²: '+format(datum.rSquared, '.2f')", "as": "R2"}
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