[R] Help with functions (iterations)

[Mark Wardle]

Dear Letticia,

Are you using R-help for your homework?

See your previous postings:


1. 15th September:

With a single R command complete the following:
create a vector calles seqvec that repeats the sequence 1, 3,6,
10,15,21.( I was trying to use c() but this does not work)
create a 5-row, 6-column matirx from seqvec wuth each row containg the
sequence from before
and complete the two task above in a single step.


2. 16th September

iven the following data for a data set called airquality. To identify
the nature of the objects from the data set airquality example "Ozone"
would it be best to use the command is. like
is.character(airquality$Ozone) ....... I tried
attributes(airquality$Ozone) but it came up null. Would there be a
better way to identify these objects.

3. 27th September

Using a 3-level input factor alternative so that a function(below) can
compute both a two-sided and one-sided p-values. Making the two-sided
test the default. And produce output information about which
alternative was tested.

4. Today

Need to create a for loop that saves the estimate of pi from each 0f
100 separate iterations and store it in a numeric vector (of length
100). The for loop should be placed in a function that allows the user
to vary the sample size, the simulation size, the integration limits
and the input function. In addition construct a histogram of the
estimates and include a red vertical line at pi.

Mark

On 29/09/2007, Letticia Ramlal <lramlal at claflin.edu> wrote:
> Hello:
> I am a bit confused by this problem. Can anyone give me some advice on this I would greatly appreciate it. Thank you for all your help.
>
> Need to create a for loop that saves the estimate of pi from each 0f 100 separate iterations and store it in a numeric vector (of length 100). The for loop should be placed in a function that allows the user to vary the sample size, the simulation size, the integration limits and the input function. In addition construct a histogram of the estimates and include a red vertical line at pi.
>
> ex1.fcn<-function(x){
> h<-4/(1+x^2)
> return(h)
> }
> n=1000
> a=0
> b=1
> my.rand.x=runif(n,min=a,max=b)
> pi.MC = ((b-a)/n)*sum(ex1.fcn(my.rand.x))
>
>
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-- 
Dr. Mark Wardle
Specialist registrar, Neurology
Cardiff, UK