[R] (no subject)

[Наталия Титова]

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.)