Search code examples
rprobabilitydistributiondata-analysisnormal-distribution

Generating samples from normal distribution

I am trying to generate many samples from normal distribution with different parameters (parametrs in a list).

How can I do this using apply family?

For example I need 2 samples one: (n = 10, mean = 2, sd = 3), and the second: (n = 100, mean = 0, sd = 1).

My code is not working.

lista <- list (c(10,2,3), c(100,0,1))
lapply(lista, rnorm, n=lista[[1]][1], mean=lista[[1]][2], sd=lista[[1]][3])

Please, help me :(

Solution

  • We can use lapply(lista, function (u) rnorm(u[1], u[2], u[3])).

    If you are not sure how to write an lapply, always start from writing a for loop. lapply(lst, FUN) is nominally a loop of this kind:

    z <- vector("list", length(lst))  ## set up a list to hold result
for (i in 1:length(lst)) z[[i]] <- FUN(lst[[i]])

    Now it should be clear that you want to do something like

    FUN <- function (u) rnorm(u[1], u[2], u[3])