How to calculate overall-mean for subsets in R

Assume I have longitudinal data (e.g. 21 countries' gdp over 5 years) with 2 variables of the same scale. data is sorted as follows

Country-year	x1	x2
USA-1	50	2
USA-2	47	1.5
USA-5	52	1.9
UK-1	63	2
UK-5	41	3

n = 21  m = 5  N = n * m  set.seed(123)  x <- MASS::mvrnorm(N, rep(0,2), diag(2))  

I want to do two things:

• First, calculate the mean country-wise
• Second, calculate the mean year-wise

For the first task, I have the following code

x_barbar <- NULL  k = 1  for(i in 1:n){   x_barbar[i] <- mean(x[k:(k + (m - 1)), ])   k = k + m  }  

How can I optimize my code for the first task and figure out a code to do the second task.

Your help is appreciated.

https://stackoverflow.com/questions/67341418/how-to-calculate-overall-mean-for-subsets-in-r May 01, 2021 at 07:09AM