Simple Linear Regression, way-to-ds-ep03

#ds

Conventional Methods – Simple Linear Regression

Defination

Predict a Y usig a single feature X by minimize the errors by a cost function.

Cost function

Mean Squared Error(L2 loss) function

Steps with code examples

Step 1: Data Preprocessing

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

dataset = pd.read_csv('dataset.csv')
X = dataset.iloc[ : ,   : 1 ].values
Y = dataset.iloc[ : , 1 ].values

from sklearn.cross_validation import train_test_split
X_train, X_test, Y_train, Y_test = train_test_split( X, Y, test_size = 1/4, random_state = 0) 

Step 2: Fitting Simple Linear Regression Model to the training set

 from sklearn.linear_model import LinearRegression
 regressor = LinearRegression()
 regressor = regressor.fit(X_train, Y_train)

#### Step 3: Predecting the Result

 Y_pred = regressor.predict(X_test)

#### Step 4: Visualization ##### Visualising the Training results

 plt.scatter(X_train , Y_train, color = 'red')
 plt.plot(X_train , regressor.predict(X_train), color ='blue')

##### Visualizing the test results

 plt.scatter(X_test , Y_test, color = 'red')
 plt.plot(X_test , regressor.predict(X_test), color ='blue')