用stata做面板数据的单位根检验,命令用hadrilm, 请问红颜色的结果是什么意思?怎么解决,谢谢
. tsset code year
panel variable: code (unbalanced)
time variable: year, 2006 to 2009, but with gaps
delta: 1 unit
. hadrilm
varlist required
r(100);
. hadrilm staff
Number of gaps in sample: 72
sample may not contain gaps
invalid syntax