3月份的时候用还没有问题，可能当时是0.8.0，现在报错了
AttributeError: 'module' object has no attribute 'api'

ps:刚刚去更新到了0.9.0，报错
  File "e:\software\Anaconda2\lib\site-packages\statsmodels\api.py", line 1, in <module>
    from . import iolib
ImportError: cannot import name iolib

有人能指导一下吗？

用法是这样的：
import pandas as pd
import numpy as np
import math
import statsmodels.api as sm

……
X = ff[['Fog1','logYsmvttl','volatility','logasset','BM','logmbincome','Analyst','INIHolder']]
Y = ff['Yretwd']
X=sm.add_constant(X)
model = sm.OLS(Y,X)
results = model.fit()
print(results.summary())
print(results.tvalues)