[R] What's wrong with ar for my data?

[zhu wang]

Dear helpers,

When I use ar to fit the data with length 180, I have the following
error:

ar(x,method="burg")
Error in acf(x, type = "covariance",lag.max=order,plot=FALSE):
         lag.max must be at least 1

If I use 

ar(x), then I have

Call (x=x)


order selected 0 sigma^2 estimated as 5374

Obviously I missed some points for using ar. 
This is R 1.7.0 under Redhat Linux 9.0
Thanks in advance.

Zhu Wang
Statistical Science Department
Southern Methodist University

-- 
zhu wang <zhuw at mail.smu.edu>