[R] Solving a normal distribution pnorm for q

[Dániel Kehl]

Looks like homework.

Try ?qnorm
________________________________________
Feladó: r-help-bounces at r-project.org [r-help-bounces at r-project.org] ; meghatalmazó: Johannes Radinger [johannesradinger at gmail.com]
Küldve: 2013. december 12. 14:56
To: R help
Tárgy: [R] Solving a normal distribution pnorm for q

Hi,



I found follwowing example of pnorm here:

http://www.r-tutor.com/elementary-statistics/probability-distributions/normal-distribution



Problem

Assume that the test scores of a college entrance exam fits a normal
distribution. Furthermore, the mean test score is 72, and the standard
deviation is 15.2. What is the percentage of students scoring 84 or more in
the exam?



Solution

> pnorm(84, mean=72, sd=15.2, lower.tail=FALSE)

[1] 0.21492



That is straight forward, however what if I want to know the score the best
30% students are reaching at least. So I know the solution of pnorm but
want to know its q. How can that be achieved in R?



Any suggestions?



/Johannes

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.