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]]
On 12-12-2013, at 14:56, Johannes Radinger <johannesradinger at gmail.com> wrote:> 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?Do ?pnorm in R. You are directed to a help page where you will also see ?qnorm?. Then try qnorm. Berend
Looks like homework. Try ?qnorm ________________________________________ Felad?: r-help-bounces at r-project.org [r-help-bounces at r-project.org] ; meghatalmazó: Johannes Radinger [johannesradinger at gmail.com] K?ldve: 2013. december 12. 14:56 To: R help T?rgy: [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.
?pnorm ... carefully...
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Johannes Radinger <johannesradinger at gmail.com>
wrote:>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.