I wrote the following R code

#Assignment 1 Q3
s=5
n=10

mstore=matrix(nrow=s,ncol=2)
for(i in 1:s)
{
x=rnorm(n)
mstore[i,1]=mean(x)
mstore[i,2]=median(x)

mx = colMeans(mstore)
}
print(mx)

you can see I stored some value in matrix, but how to find the variance of stored mean and median in the matrix?