I have a data set like: Growth NHSPSTY% Index USURTOT Index GLPFTOCI Index CPTICHNG Index NAPMPMI Index RSTAXYOY Index SAARTOTL Index USASHVTK Index CONCCONF Index LEI TOTL Index SPX Index TOT_DEBT_TO_TOT_EQY BDIY Index cry index CO1 Comdty Date 1998-03-31 4.1 7.5 4.7 0.121000 83.5325 52.9 2.9 -0.032258 0.404 133.80 88.9 0.455185 197.26 966 169.04 14.26 1998-06-30 3.8 9.8 4.5 0.125556 82.2970 48.9 4.5 0.154930 0.393 138.23 88.6 0.280973 204.65 856 152.58 13.38 I wanted to run a OLS regression but all the parameters returned all nan values. And it warned: /Users/jake/anaconda3/lib/python3.6/site-packages/scipy/stats/_distn_infrastructure.py:879: RuntimeWarning: invalid value encountered in greater return (self.a < x) & (x < self.b) /Users/jake/anaconda3/lib/python3.6/site-packages/scipy/stats/_distn_infrastructure.py:879: RuntimeWarning: invalid value encountered in less return (self.a < x) & (x < self.b) /Users/jake/anaconda3/lib/python3.6/site-packages/scipy/stats/_distn_infrastructure.py:1821: RuntimeWarning: invalid value encountered in less_equal cond2 = cond0 & (x <= self.a) coef std err t P>|t| [0.025 0.975] const nan nan nan nan nan nan NHSPSTY% Index nan nan nan nan nan nan USURTOT Index nan nan nan nan nan nan GLPFTOCI Index nan nan nan nan nan nan CPTICHNG Index nan nan nan nan nan nan My command: import statsmodels.api as sm model = sm.OLS(data.Growth,sm.add_constant(data.iloc[:,1:])).fit() model.summary() Continue reading...