Please read the Posting Guide mentioned at the bottom of every message on this list. There is a "no homework" policy. Please refer to your assistance options available through your educational institution. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<[email protected]> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity.
Eva-Lotta Blom <[email protected]> wrote: > >1. Emma is performing an experiment that requires individual handling >of some animals. The sizes of the animals are lognormally distributed: >The natural logarithms of their sizes has a normal distribution with >mean 3 and standard deviation 0.4. The time (in minutes) it takes to >handle each animal is given by > >10 + s �� 1.5 + e�� for animals with s ��� 20 20 + s �� 0.8 + e�� for >animals with s > 20 > >where �� is a random variable that is normally distributed with >expectation 1 and variance 0.3. > >For a randomly picked animal, what is the (approximate) probability >that it can be handled in less than 30 minutes? > >We can solve this exercise using simulation, as follows: Simulate a >vector S with the sizes of 10000 animals, by using the rnorm function >and the ���exp��� function. Then, compute a vector Time of length 10000 >with the times it takes to handle each of these 10000 animals: Remember >that to separate between the two cases, you can use notation like for >example ���Time[S < 20]���. The random component e�� can be added by >combining the ���exp��� function with the ���rnorm��� function. >Finally, you can find the proportion of simulated values below 30. >Re-do the computations a couple of times to get an idea of the >variability of the result. > >s <- c(10000) >S <- exp(rnorm(s, 3, 0.4)) [1]# vector 10000, mean, sd >Time <- 10+S*1.5 [1] # 10 + s �� 1.5 + e�� for animals with s ��� 20 >time <- 20+S*0.8 [1] # 20 + s �� 0.8 + e�� for animals with s > 20 > >can't get any further and i can't really find a good help page to solve >the code. >can you help me? >Lotta > >------------------------------------------------------------------------------------ >Eva-Lotta Blom PhD student >Dept. of BioEnv . Tj��rn�� >University of Gothenburg >452 96 Str��mstad >Sweden > > > > > > > > [[alternative HTML version deleted]] > >______________________________________________ >[email protected] 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. ______________________________________________ [email protected] 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.
