ID Year Temp NTemp Temp - NTemp
1 1990 10 12 -2
1 1991 12 12 0
1 1992 14 12 2
2 1990 12 13 -1
2 1991 13 13 0
2 1992 14 13 1
3 1990 13 14 -1
3 1991 14 14 0
3 1992 15 14 1
I need some help with panel data.
I've a big dataset.
A simplified version is above.

Temp is temperature.
NTemp is normal temperature.
NTemp is calculated by averaging Temp in all years within a group.
I want to calculate deviation from normal temperature i.e. Temp-NTemp

Can you tell me how can I do the same in STATA using commands?

Thanks,