r2_calc.ipynb

{
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  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "from sklearn.linear_model import LinearRegression"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "x = range(1, 10 + 1)\n",
    "x = np.array(x)[:, np.newaxis]\n",
    "y = np.exp(x)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "LinearRegression(copy_X=True, fit_intercept=True, n_jobs=1, normalize=False)"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lr = LinearRegression()\n",
    "lr.fit(x, y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0.5139031732249719"
      ]
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     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lr.score(x, y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[-3962.96101439],\n",
       "       [-2307.99692574],\n",
       "       [ -653.03283709],\n",
       "       [ 1001.93125156],\n",
       "       [ 2656.89534021],\n",
       "       [ 4311.85942886],\n",
       "       [ 5966.82351751],\n",
       "       [ 7621.78760616],\n",
       "       [ 9276.75169481],\n",
       "       [10931.71578346]])"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
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   "source": [
    "lr.predict(x)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [],
   "source": [
    "ss_tot = np.sum((y - np.mean(y)) ** 2)\n",
    "ss_res = np.sum((lr.predict(x) - y) ** 2)"
   ]
  },
  {
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   "execution_count": 17,
   "metadata": {},
   "outputs": [
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     "execution_count": 17,
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     "output_type": "execute_result"
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   "source": [
    "ss_tot"
   ]
  },
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   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "213733493.2899452"
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     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
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    "ss_res"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0.5139031732249719"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "r2 = 1 - ss_res / ss_tot\n",
    "r2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Resources"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "https://www.wikiwand.com/en/Coefficient_of_determinationm"
   ]
  }
 ],
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