# [R] (no subject)

Spencer Graves spencer.graves at pdf.com
Fri Sep 17 19:54:45 CEST 2004

```      Have you considered "predict.lm", at least in R 1.9.1?  (If I
understand your question, it is answered in the "examples" to
"predict.lm".)

hope this helps.
p.s.  I believe this is described in Venables and Ripley, Modern Applied
Statistics with S, but I don't have this book at my fingertips.  Also,
have you read the posting" guide!
http://www.R-project.org/posting-guide.html"?  Its suggestions might
help you get quicker answers for yourself without waiting for this list
to reply and might improve the quality of the replies to questions you
submit.

ц╝ц│ц■ц│ц▄ц┴ц▒ ц╢ц┴ц■ц▐ц≈ц│ wrote:

>I have one problem with finding the appropriate functions in R that would perform this operation: We have X, the independent variable, and Y, the response variable, so that a regression line of these variables can be calculated. Using the Student t distribution, we need to find the 95% prediction interval of the mean of Y for the certain value of X. For example, R has the built-in data ( data(cars) ) for cars' speed as the independent variable and cars' stopping distance as the response variable. Find 95% prediction interval of mean stopping distance for cars speeding at 30.
>
>I have another question: is there a certain function in R that can calculate the probability p using the Student t distribution given the certain value, the sample mean, and the sample standard deviation, and df (i.e., the one that functions like pnorm(), but deals with Student t distribution.)
>
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>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>
>

--
Spencer Graves, PhD, Senior Development Engineer
O:  (408)938-4420;  mobile:  (408)655-4567

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