title: Scikit Learn Not fit error when calling LinearRegression
body: <p>I am calling LinearRegression using this code in Spyder:</p>
  
  <pre><code> X = Full[predictors]
  Y = Full['logerror']
  X_train, X_test, Y_train, Y_test = train_test_split( X, Y, test_size=0.2, random_state=42)
  
  X_train_val = X_train.values
  Y_train_val = Y_train.values
  X_test_val = X_test.values
  
  
  model = LinearRegression()
  
  LinearRegression(copy_X=True, fit_intercept=True, n_jobs=1, normalize=False)
  
  pred = model.predict(X_test_val)
  </code></pre>
  
  <p>it shows this error: NotFittedError: This LinearRegression instance is not fitted yet.</p>
  
  <p>How should I fix it?</p>