-----Original Message-----
From: kelly johnson [mailto:[email protected]]
Sent: Tuesday, July 12, 2005 9:51 PM
Hi,
Quick question: suppose I have a variable like this:
N Var1
1 12
2 45
3 65
100 15
How can I create a new variable whose first observation is the average
of
Var1[1] and Var1[2], second observation is the avaerage of Var1[3] and
Var1[4], etc. There will be a total of 50 observations for this new
variable. Thanks in advance!
Not quite. That creates the even-numbered obs. of Var2 as the desired
values, with the odd-numbered values equal to missing. To fix that up,
thanks to Bill Gould's excellent tutorial at this morning's Boston SUG
meeting, you may use a cute mata trick (in Stata 9, anyway):
clear
set obs 100
g Var1=_n
g Var2=(Var1+Var1[_n-1])/2 if mod(_n,2)==0
mata:
v = st_data(.,"Var2",0) // grab nonmissing elements of Var2
null=J(50,1,.)
v = v\null // append 50 missings
st_store(.,2,v) // stuff it back in Var2
end
list
