Imagine I have the following base:
Country <- c("Brazil", "Brazil", "Brazil", "Brazil", "Brazil","Brazil", "Argentina", "Argentina", "Argentina", "Argentina", "Argentina", "Argentina")
Year <- c(91, 92, 93, 94, 95, 96, 91, 92, 93, 94, 95, 96)
period <- c(1, 1, 2, 2, 3, 3, 1, 1, 2, 2, 3, 3)
values <- c(5,3, 4, 2, 1, 1, 5, 7, 4, 4, 3, 7)
df <- data.frame(country = Country, year = Year, period = period, pib = values)
country year period value
Brazil 91 1 5
Brazil 92 1 3
Brazil 93 2 4
Brazil 94 2 2
Brazil 95 3 1
Brazil 96 3 1
Argentina 91 1 5
Argentina 92 1 7
Argentina 93 2 4
Argentina 94 2 4
Argentina 95 3 3
Argentina 96 3 7
From this base I want to create a new variable called media, where the average GDP will be calculated for each country in each period, so that the final result would be:
country year period pib media
Brazil 91 1 5 4
Brazil 92 1 3 4
Brazil 93 2 4 3
Brazil 94 2 2 3
Brazil 95 3 1 1
Brazil 96 3 1 1
Argentina 91 1 5 6
Argentina 92 1 7 6
Argentina 93 2 4 4
Argentina 94 2 4 4
Argentina 95 3 3 5
Argentina 96 3 7 5
I have no idea how to do this, but I believe there is a way. Can someone give me a light?
PS: I tried to create the best possible example, but I'm still a beginner.