R, Statistics, Data Science.
## [3,] 0.33226458 2.3553885 6.1139354 3.781044 ## [4,] 0.20847000 1.6371084 3.7810438 2.493091 E = matrix(data = 0, nrow = 4, ncol = 4) for (i in 1:dim(E)[1]) { for (j in 1:i) { b <- c() for (k in root.group) { a <- sum((k[,i] - mean(k[,i])) * (k[,j] - mean(k[,j]))) b <- append(b, a) } E[i,j] <-