R help - Jun 2009 - simulating Likert-type data

Dear R members

Could someone indicate me how to simulate Likert-type data using the GAMLSS
library and how to fit that data?

Let?s say, 50 random numbers in a variable that goes from -4 to +4 in steps of
1 (i.e., -4, -3, -2, -1, 0, 1, 2, 3, 4) with a mean of 2 and SD of 0.15 and
belonging to a normal distribution?

Cheers

Fer

Fernando Marmolejo Ramos wrote:
> Dear R members
>
> Could someone indicate me how to simulate Likert-type data using the GAMLSS
> library and how to fit that data?
>
> Let?s say, 50 random numbers in a variable that goes from -4 to +4 in steps
of
> 1 (i.e., -4, -3, -2, -1, 0, 1, 2, 3, 4) with a mean of 2 and SD of 0.15 and
> belonging to a normal distribution?
>
>   
Hi Fernando,
You can get something like a truncated normal (in the sense of, "If I 
squint my eyes right down, it looks kind of normal") sample with:

sample(-4:4,50,TRUE,prob=c(pnorm(-4:2,)pnorm(c(3,4),2,lower.tail=FALSE))

but it will not pass any of the usual tests for normal distribution.

Jim

Oops, sorry. Sloppy translation from the R window
>
>
sample(-4:4,50,TRUE,prob=c(pnorm(-4:2,2,0.15)pnorm(c(3,4),2,0.15,lower.tail=FALSE))
>
Jim