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- {
- "cells": [
- {
- "cell_type": "markdown",
- "metadata": {
- "collapsed": true
- },
- "source": [
- "###REGRESION LINEAR "
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 1,
- "metadata": {},
- "outputs": [],
- "source": [
- "import math\n",
- "from matplotlib import pyplot as plt\n",
- "import numpy as np\n",
- "import random\n",
- "from collections import Counter"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 2,
- "metadata": {},
- "outputs": [],
- "source": [
- "def dot(v, w):\n",
- " \"\"\"v_1 * w_1 + ... + v_n * w_n\"\"\"\n",
- " return sum(v_i * w_i for v_i, w_i in zip(v, w))\n",
- "def sum_of_squares(v):\n",
- " \"\"\"v_1 * v_1 + ... + v_n * v_n\"\"\"\n",
- " return dot(v, v)\n",
- "def mean(x):\n",
- " return sum(x)/len(x)\n",
- "def de_mean(x):\n",
- " x_bar=mean(x)\n",
- " return [x_i-x_bar for x_i in x]\n",
- "def covariance(x,y):\n",
- " n=len(x)\n",
- " return dot(de_mean(x),de_mean(y))/(n-1)\n",
- "def variance(x):\n",
- " n = len(x)\n",
- " deviations = de_mean(x)\n",
- " return sum_of_squares(deviations) / (n - 1) #esta sum_of_squares \n",
- " # viene de la hoja python Algebra linear!!!!!!!!!!!!!!!\n",
- "def standard_deviation(x):\n",
- " return math.sqrt(variance(x))\n",
- "def correlation(x,y):\n",
- " stdev_x=standard_deviation(x)\n",
- " stdev_y=standard_deviation(y)\n",
- " if stdev_x>0 and stdev_y>0:\n",
- " return covariance(x,y)/stdev_x/stdev_y\n",
- " else:\n",
- " return 0"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###1-definiendo la funcion predictora"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 3,
- "metadata": {},
- "outputs": [],
- "source": [
- "def predict(alpha,beta,x_i):\n",
- " return beta*x_i+alpha"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###2-definiendo la funcion para el calculo de error"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 4,
- "metadata": {},
- "outputs": [],
- "source": [
- "def error(alpha,beta, x_i,y_i):\n",
- " #error de prever beta*x_i+alpha quando o valor real é y_i\n",
- " return y_i-predict(alpha,beta,x_i)"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###3-definiendo la funcion para la suma de los cuadrados de los errores"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 5,
- "metadata": {},
- "outputs": [],
- "source": [
- "def sum_of_squared_errors(alpha, beta, x, y):\n",
- " return sum(error(alpha, beta, x_i, y_i) ** 2\n",
- " for x_i, y_i in zip(x, y))"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###4-definiendo la funcion que minimiza los errores de alpha y beta"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 6,
- "metadata": {},
- "outputs": [],
- "source": [
- "def least_squares_fit(x,y):\n",
- " #datos y valores en entrenamiento para 'x' y 'y' encuentran los valores minimos de los cuadrados de alpha y beta\n",
- " beta=correlation(x,y)*standard_deviation(y)/standard_deviation(x)\n",
- " alpha=mean(y)-beta*mean(x)\n",
- " return alpha, beta"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###datos para realizar el analisis"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 7,
- "metadata": {},
- "outputs": [],
- "source": [
- "num_friends = [100,49,41,40,25,21,21,19,19,18,18,16,15,15,15,15,14,14,13,13,13,13,12,12,11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,8,8,8,8,8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]\n",
- "daily_minutes = [1,68.77,51.25,52.08,38.36,44.54,57.13,51.4,41.42,31.22,34.76,54.01,38.79,47.59,49.1,27.66,41.03,36.73,48.65,28.12,46.62,35.57,32.98,35,26.07,23.77,39.73,40.57,31.65,31.21,36.32,20.45,21.93,26.02,27.34,23.49,46.94,30.5,33.8,24.23,21.4,27.94,32.24,40.57,25.07,19.42,22.39,18.42,46.96,23.72,26.41,26.97,36.76,40.32,35.02,29.47,30.2,31,38.11,38.18,36.31,21.03,30.86,36.07,28.66,29.08,37.28,15.28,24.17,22.31,30.17,25.53,19.85,35.37,44.6,17.23,13.47,26.33,35.02,32.09,24.81,19.33,28.77,24.26,31.98,25.73,24.86,16.28,34.51,15.23,39.72,40.8,26.06,35.76,34.76,16.13,44.04,18.03,19.65,32.62,35.59,39.43,14.18,35.24,40.13,41.82,35.45,36.07,43.67,24.61,20.9,21.9,18.79,27.61,27.21,26.61,29.77,20.59,27.53,13.82,33.2,25,33.1,36.65,18.63,14.87,22.2,36.81,25.53,24.62,26.25,18.21,28.08,19.42,29.79,32.8,35.99,28.32,27.79,35.88,29.06,36.28,14.1,36.63,37.49,26.9,18.58,38.48,24.48,18.95,33.55,14.24,29.04,32.51,25.63,22.22,19,32.73,15.16,13.9,27.2,32.01,29.27,33,13.74,20.42,27.32,18.23,35.35,28.48,9.08,24.62,20.12,35.26,19.92,31.02,16.49,12.16,30.7,31.22,34.65,13.13,27.51,33.2,31.57,14.1,33.42,17.44,10.12,24.42,9.82,23.39,30.93,15.03,21.67,31.09,33.29,22.61,26.89,23.48,8.38,27.81,32.35,23.84]"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 8,
- "metadata": {},
- "outputs": [],
- "source": [
- "#calculo de la correlacion sin outliers\n",
- "outlier=num_friends.index(100)\n",
- "num_friends_good=[x for i,x in enumerate(num_friends)\n",
- " if i !=outlier]\n",
- "daily_minutes_good=[x for i,x in enumerate(daily_minutes)\n",
- " if i !=outlier]"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###5-determinando alpha y beta"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 9,
- "metadata": {},
- "outputs": [],
- "source": [
- "#aqui estamos haciendo el calculo tomando el ejemplo del capitulo 5.\n",
- "alpha,beta=least_squares_fit(num_friends_good,daily_minutes_good)"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 10,
- "metadata": {},
- "outputs": [
- {
- "data": {
- "text/plain": [
- "22.94755241346903"
- ]
- },
- "execution_count": 10,
- "metadata": {},
- "output_type": "execute_result"
- }
- ],
- "source": [
- "alpha"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 11,
- "metadata": {},
- "outputs": [
- {
- "data": {
- "text/plain": [
- "0.903865945605865"
- ]
- },
- "execution_count": 11,
- "metadata": {},
- "output_type": "execute_result"
- }
- ],
- "source": [
- "beta"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "###6-determinando la suma de cuadrados totales"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 12,
- "metadata": {},
- "outputs": [],
- "source": [
- "def total_sum_of_squares(y):\n",
- " #la suma total de los cuadrados de las variaciones de y_i a partir se sus medias\n",
- " return sum(v**2 for v in de_mean(y))"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "#7-definiendo R cuadrado"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 13,
- "metadata": {},
- "outputs": [],
- "source": [
- "def r_squared(alpha,beta,x,y):\n",
- " return 1.0-(sum_of_squared_errors(alpha,beta,x,y)/total_sum_of_squares(y))"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 15,
- "metadata": {},
- "outputs": [
- {
- "data": {
- "text/plain": [
- "0.3291078377836305"
- ]
- },
- "execution_count": 15,
- "metadata": {},
- "output_type": "execute_result"
- }
- ],
- "source": [
- "r_squared(alpha,beta,num_friends_good,daily_minutes_good)"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": null,
- "metadata": {},
- "outputs": [],
- "source": [
- ""
- ]
- }
- ],
- "metadata": {
- "kernelspec": {
- "display_name": "Python 2",
- "language": "python",
- "name": "python2"
- },
- "language_info": {
- "codemirror_mode": {
- "name": "ipython",
- "version": 2.0
- },
- "file_extension": ".py",
- "mimetype": "text/x-python",
- "name": "python",
- "nbconvert_exporter": "python",
- "pygments_lexer": "ipython2",
- "version": "2.7.6"
- }
- },
- "nbformat": 4,
- "nbformat_minor": 0
- }
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