I want to test for panel unit root using "pCARDtest" but it returns: function cannot be found. I want help on this.
I tried the CIPS test for panel unit root too. But it also returned an error(attached below).
cipstest(CCA, type = "drift")
Error in approx(nintv, cvals[nintl:ninth, tintl, i], n = max(nintv) - :
need at least two non-NA values to interpolate
A reproducible example, called a reprex is essential for an answer to the pCARDtest question, together with URL for the related package if it's not on CRAN.
The second question relates to the object on which you are trying to apply cipstest, which apparently interpolates values. Are there *at least two-NA values`?