answer to my previous question

[Muyin Wang <muyin@xxxxxxxxxxxxx>]

I was suggested that to post the answer I had for my question to the network. So
here it is: 
In order to get the means of different time period, you have to set it within
the command. So the correct way for the following example is given below:

----Original way, which does not work:
define axis/t=1:209:1 tax
define grid/t=tax mygrd
let temp=2*l[g=mygrd]
let apr = if (mod(l,12) eq 4) then temp
set region/l=9:110
let/title=apr1 aprav1=apr[l=@ave]
list aprav1
can region
set region/l=111:206
let/title=apr2 aprav2=apr[l=@ave]

------
In this way the apr1 and apr2 are changing as the region changes. So to make
sure
they are for each time period, the correct definition is:

let/title=apr1 aprav1=apr[l=9:110@ave]
let/title=apr2 aprav2=apr[l=111:206@ave]

Then their values (aprav1 & aprav2) will be reserved