Code:

```
library(urca)
data(Raotbl3)
attach(Raotbl3)
lc.df <- ur.df(y=lc, lags=3, type='trend')
summary(lc.df)
```

There are three hypothesis the one I care about is non-stationarity

- tau3 refers to the null hypothesis that there is a unit root.
- phi3 refers to the null hypothesis that there is a unit root AND no-trend (without trend)
- phi2 refers to the null hypothesis that there is a unit root without trend and without drift

The problem is that the output lists three critical values

Value of test-statistic is: -2.2389 3.7382 2.5972

I have no idea which you use. Unless the first one is for tau3, the next for phi3 and the last for phi2