library(mvtnorm)
library(matlib)
The ggplot2 package [46] is for plotting. Then, we define the mean and the standard deviation as:
## Standard deviation
sigma <- matrix(c(4,2,2,3), ncol = 2, nrow = 2)
## Mean
mu <- c(1, 2)
For this data we have the sample size n = 10000.
n <- 1000
The function set.seed() sets the seed, which is a value to start generating random numbers. The set.seed() function resets the values of the random numbers and random functions from the values previously obtained. We set a seed in order to reproduce the same outcome. If we set the same seed, then we can reproduce the same random numbers:
set.seed(123)
Finally, we generate the data points by
x <- rmvnorm(n = n, mean = mu, sigma = sigma)
To plot the data we set the points in a data frame:
d <- data.frame(x)
Using the ggplot2 package we plot the data points as
y <- x - mu
E <- eigen(sigma)
E$vectors
## [,1] [,2]
## [1,] -0.7882054 0.6154122
## [2,] -0.6154122 -0.7882054