crystal8832 发表于 2015-11-25 12:56 
您先看下数据类型是否有误,需要是数值型的,另外把检验后提示的问题发出来看下
您好!按照上面的命令:
findit xtunitroot
. webuse pennxrate
xtunitroot fisher y,dfuller lag(0)
结果是:
Fisher-type unit-root test for y
Based on Phillips-Perron tests
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Ho: All panels contain unit roots Number of panels = 10
Ha: At least one panel is stationary Number of periods = 33
AR parameter: Panel-specific Asymptotics: T -> Infinity
Panel means: Included
Time trend: Not included
Newey-West lags: 0 lags
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Statistic p-value
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Inverse chi-squared(20) P 201.4979 0.0000
Inverse normal Z -11.9776 0.0000
Inverse logit t(54) L* -17.7292 0.0000
Modified inv. chi-squared Pm 28.6973 0.0000
------------------------------------------------------------------------------
P statistic requires number of panels to be finite.
Other statistics are suitable for finite or infinite number of panels.
------------------------------------------------------------------------------
以上结果中的字母分别代表什么含义?判断是否单位根的话应该是看p值,怎么判断?
差分之后的命令:
gen dy=D.y
findit xtunitroot
. webuse pennxrate
xtunitroot fisher dy,dfuller lag(0)
结果提示:
xtunitroot fisher dyl,dfuller lag(1)
(10 missing values generated)
performing unit-root test on first panel using the syntax dfuller dy, lags(1)
returned error code 2000
r(2000);
除了什么问题?命令要怎么修改?麻烦您给解答一下!万分感激!