我想根据id分组,每组累积计算x的峰度y。例如id=1时,生成新变量y,y[1]是5.207的峰度,y[2]是(5.207,4.976)的峰度,y[3]是(5.207,4.976,3.953)的峰度,……;id=2时,y[1]是4.403的峰度,y[2]是(4.403,4.773)的峰度,y[3]是(4.403,4.773,4.712)的峰度,……。请帮忙看看有什么好的办法吗?
- * Example generated by -dataex-. For more info, type help dataex
- clear
- input long id int year double x
- 1 1997 5.207
- 1 1998 4.976
- 1 1999 3.953
- 1 2000 4.484
- 1 2001 5.701
- 1 2002 6.901
- 1 2003 7.424
- 1 2004 7.871
- 1 2005 8.218
- 1 2006 8.569
- 1 2007 8.776
- 1 2008 8.566
- 1 2009 8.658
- 1 2010 8.907
- 2 1997 4.403
- 2 1998 4.773
- 2 1999 4.712
- 2 2000 5.148
- 2 2001 5.822
- 2 2002 6.248
- 2 2003 6.598
- 2 2004 7.412
- 2 2005 8.047
- 2 2006 8.487
- 2 2007 8.632
- 2 2008 8.571
- 2 2009 8.658
- 2 2010 8.975
- end
复制代码