[R] sciplot question

[Jarle Bjørgeengen]

Great,

thanks Manuel.

Just for curiosity, any particular reason you chose standard error ,  
and not confidence interval as the default (the naming of the plotting  
functions associates closer to the confidence interval .... ) error  
indication .

- Jarle Bjørgeengen

On May 24, 2009, at 3:02 , Manuel Morales wrote:

> You define your own function for the confidence intervals. The  
> function
> needs to return the two values representing the upper and lower CI
> values. So:
>
> qt.fun <- function(x) qt(p=.975,df=length(x)-1)*sd(x)/sqrt(length(x))
> my.ci <- function(x) c(mean(x)-qt.fun(x), mean(x)+qt.fun(x))
>
> lineplot.CI(x.factor = dose, response = len, data = ToothGrowth,
>    ci.fun=my.ci)
>
> Manuel
>
> On Fri, 2009-05-22 at 18:38 +0200, Jarle Bjørgeengen wrote:
>> Hi,
>>
>> I would like to have lineplot.CI and barplot.CI to actually plot
>> confidence intervals , instead of standard error.
>>
>> I understand I have to use the ci.fun option, but I'm not quite sure
>> how.
>>
>> Like this :
>>
>>> qt(0.975,df=n-1)*s/sqrt(n)
>>
>> but how can I apply it to visualize the length of the student's T
>> confidence intervals rather than the stdandard error of the plotted
>> means ?
>>
> -- 
> http://mutualism.williams.edu
>