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    "# Tetrachoric Correlation\n",
    "\n",
    "Tetrachoric correlation in statsample requires installation of the statsample-bivariate-extension gem. This gem extends the Statsample::Bivariate class with useful algorithms for polychoric and tetrachoric correlation.\n",
    "\n",
    "Statsample will automatically detect presence of polychoric/tetrachoric algorithms so there is no need to explicitly require the gem.\n",
    "\n",
    "In this example we'll see how tetrachoric correlation can be performed using statsampl"
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     "text": [
      "Analysis 2015-06-04 16:06:58 +0530\n",
      "= Statsample::Bivariate::Tetrachoric\n",
      "  == Tetrachoric correlation\n",
      "    Contingence Table\n",
      "+-----+-----+-----+-----+\n",
      "|     | Y=0 | Y=1 |  T  |\n",
      "+-----+-----+-----+-----+\n",
      "| X=0 | 40  | 10  | 50  |\n",
      "| X=1 | 20  | 30  | 50  |\n",
      "+-----+-----+-----+-----+\n",
      "| T   | 60  | 40  | 100 |\n",
      "+-----+-----+-----+-----+\n",
      "\n",
      "    r: 0.607\n",
      "    SE: 0.115\n",
      "    Threshold X: 0.000 \n",
      "    Threshold Y: 0.253 \n",
      "\n"
     ]
    }
   ],
   "source": [
    "require 'statsample'\n",
    "\n",
    "Statsample::Analysis.store(Statsample::Bivariate::Tetrachoric) do\n",
    "  a = 40\n",
    "  b = 10\n",
    "  c = 20\n",
    "  d = 30\n",
    "  # The 'tetrachoric' shorthand calls the Statsample::Bivariate::Tetrachoric class internally\n",
    "  summary tetrachoric(a,b,c,d)\n",
    "end\n",
    "\n",
    "Statsample::Analysis.run_batch"
   ]
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