Created
April 10, 2013 15:57
-
-
Save brentp/5355925 to your computer and use it in GitHub Desktop.
calculate t statistics and p-values for coefficients in Linear Model in python, using scikit-learn framework.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
from sklearn import linear_model | |
from scipy import stats | |
import numpy as np | |
class LinearRegression(linear_model.LinearRegression): | |
""" | |
LinearRegression class after sklearn's, but calculate t-statistics | |
and p-values for model coefficients (betas). | |
Additional attributes available after .fit() | |
are `t` and `p` which are of the shape (y.shape[1], X.shape[1]) | |
which is (n_features, n_coefs) | |
This class sets the intercept to 0 by default, since usually we include it | |
in X. | |
""" | |
def __init__(self, *args, **kwargs): | |
if not "fit_intercept" in kwargs: | |
kwargs['fit_intercept'] = False | |
super(LinearRegression, self)\ | |
.__init__(*args, **kwargs) | |
def fit(self, X, y, n_jobs=1): | |
self = super(LinearRegression, self).fit(X, y, n_jobs) | |
sse = np.sum((self.predict(X) - y) ** 2, axis=0) / float(X.shape[0] - X.shape[1]) | |
se = np.array([ | |
np.sqrt(np.diagonal(sse[i] * np.linalg.inv(np.dot(X.T, X)))) | |
for i in range(sse.shape[0]) | |
]) | |
self.t = self.coef_ / se | |
self.p = 2 * (1 - stats.t.cdf(np.abs(self.t), y.shape[0] - X.shape[1])) | |
return self |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
You can try the following:
from sklearn.feature_selection import f_regression
f_statistic, p_value = f_regression(X, y)