Hi,

I have a dataset put together from the Penn World Tables, and I'm working to understand the relationship between growth in GDP per capita, and the standard deviation of the growth rate of GDP per capita. I would like to get panel data and run a time fixed effects regression, where the dependent variable is the growth rate of GDP per capita over each 10-year period (I suppose my final period, 2010-2017, would have to be 8 years). However, I am completely at a loss for how to make my dataset into decade intervals of averages and standard deviations of annual data.... My data looks like this currently:
country year decade growth_gdppc
Argentina 1970 1
Argentina 1971 1 0.0135
Argentina 1972 1 0.0003
... ... ... ...
Argentina 1983 2 0.0328
... ... ... ...
Argentina 2017 5 0.0237
Australia 1970 1
Australia 1971 1 0.0190
... ... ... ...
Australia 2017 5 0.0136
And, I suppose I would like something like this:
country decade avg_growth_gdppc_by_decade st_dev_gdppc_by_decade
Argentina 1 0.012 0.03
Argentina 2
Argentina 3 ... ...
Argentina 4
Argentina 5
Australia 1
... ... ... ...
Then, I could run a regression of avg_growth_gdppc_by_decade on st_dev_gdppc_by_decade with time fixed effects.

Apologies if anything is unclear here, this is my first time working with time variant stuff on Stata and I am very confused. I have tried to simplify things as much as possible.