# [R] generating points over a function, its possible???

Huntsinger, Reid reid_huntsinger at merck.com
Fri Jun 21 21:50:48 CEST 2002

```You can use R's random-number generating functions (e.g. rnorm) to generate
a vector of independent "deviations" from the line, and add them to your y
vector. You can scale them to make the variance match your 13.01403, usually
with a parameter to the function, or simply by multiplying by the
appropriate scale factor. You can get dependent deviations in various ways,
e.g., see "filter" in the ts package for autocorrelated or moving-average
structures. Also check the "mvnorm" package.

Reid Huntsinger

-----Original Message-----
From: Ronaldo Reis Jr. [mailto:chrysopa at insecta.ufv.br]
Sent: Friday, June 21, 2002 12:49 PM
To: R-Help
Subject: [R] generating points over a function, its possible???

Hi,
I have a new (for me) situation.
I have a function for one linear model:
y = 9.7909-0.035*x
I have the variance of system
var = 13.01403
Is possible to create a random vector points of Y (simulating the real data)

over this curve using the function and the variance? I need this to a
discipline.

I have this:

| \
|  \ -> y = 9.7909-0.035*x and var =  13.014
|   \
|    \
|     \
|      \
|__________

I need something like this (generate this points):

|* \*
| * \**
|  **\ *
|    *\ **
|    * \*
|     * \ *
|       *\
|____________

Thanks for all
Ronaldo
--
"It ain't over until it's over."
-- Casey Stengel
--
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```