# Re: st: A calculation problem

 From "Michael Blasnik" <[email protected]> To <[email protected]> Subject Re: st: A calculation problem Date Mon, 25 Sep 2006 18:10:58 -0400

reshape long v p, i(obs) j(cropvarnum)
rename v crop
rename p price

You will now have 1 observation for each crop/price combo. You can get the mean price for each crop type by

by crop: egen meanprice=mean(price)

This calculation will ignore missing values. You can also use commands like summarize and table and tabstat to get means or other summaries displayed. If you just want one observation with the mean of each crop, you could use collapse instead of egen mean...

Michael Blasnik

Jia Xiangping wrote:
> Dear friends,
>
> I have been annoyed by one problem for several days, and I am unable
> to work it out. Sincerely wish you can give me a hand. I believe after
> suffering from this, I can expect some improvement.
>
>
> obs v25 v38  v51 v64 p25  p38  p51  p64
> 1    01   12  39        0.7   1.8   0.6   0.5
> 2    01   19  21         .     1.6   0.8   0.7
> 3    01   34  19        0.6   .      0.6    0.7
> 4    09   19  01        1.5   0.9   0.9
> 5   19    25  07
> 6   12    31
> 7   25
>
>
>
> While v25 v38 v51……stand for the code of different crops, p25 p38
> p51…stand for the correspond price. Things become remarkably tricky
> when some price are missing. For example, crop 01 has price 0.7 in
> observation 1, but price is missing in observation 2.
>
> Now I want to calculate the average price of different crops. Is that
> possible? I am now like an ant on hot brick.
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