I have three problems I am trying to simulate, that I am having difficulty
getting around with.
Problem 1.
I want to determine the 85 percentile (the x value for which the sum of
probabilities becomes 0.85) of the following distributions (two binomials
and a Poisson with rate Lmbda= np of the two binomials): X ~B(10, 0.3),
Y~P(3) ,
Z~B(30, 0.1). I want to show that that Y is a good approximation for Z but
not for X...(by examining these distributions for few
different percentiles)
Problem 2:
For a binomial distribution X ~ B(20, 0.4), I want to use R to calculate
P{|X ? ?| < 2} and verify that it is near or larger than 0.95. (Hint from
the text book: Since ? = 8 and 2.3 then you may want to read the
weights, or probabilities, of the values 6:10, into a vector v and then use
the command sum(v) to
calculate the sum.) Repeat this for another set of parameters of your
choice.
Problem 3:
Draw a sample of size 10, from a Poisson with Lambda= 5, and calculate the
mean and the standard deviation of this sample, Repeat this calculation with
size 20 and 30 and demonstrate
that ?X gets closer to ? as the sample size increases.
Thanks.
I would appreciate it if someone accompanied the codes with a brief
explanation so I can be able to replicate it myself.
--
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From the R Posting Guide: Basic statistics and classroom homework: R-help is not intended for these. On Mon, 19 Nov 2007, Epselon wrote:> > I have three problems I am trying to simulate, that I am having difficulty > getting around with. > > Problem 1. > I want to determine the 85 percentile (the x value for which the sum of > probabilities becomes 0.85) of the following distributions (two binomials > and a Poisson with rate Lmbda= np of the two binomials): X ~B(10, 0.3), > Y~P(3) , > Z~B(30, 0.1). I want to show that that Y is a good approximation for Z but > not for X...(by examining these distributions for few > different percentiles) > > Problem 2: > For a binomial distribution X ~ B(20, 0.4), I want to use R to calculate > P{|X ? ?| < 2} and verify that it is near or larger than 0.95. (Hint from > the text book: Since ? = 8 and 2.3 then you may want to read the > weights, or probabilities, of the values 6:10, into a vector v and then use > the command sum(v) to > calculate the sum.) Repeat this for another set of parameters of your > choice. > > Problem 3: > Draw a sample of size 10, from a Poisson with Lambda= 5, and calculate the > mean and the standard deviation of this sample, Repeat this calculation with > size 20 and 30 and demonstrate > that ?X gets closer to ? as the sample size increases. > > Thanks. > > I would appreciate it if someone accompanied the codes with a brief > explanation so I can be able to replicate it myself. > -- > View this message in context: http://www.nabble.com/Trying-to-get-around-R-tf4837183.html#a13838643 > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. >Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:cberry at tajo.ucsd.edu UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
Hello Epselon (if that is your name), This sounds like homework questions. From the R-help posting guide: "Basic statistics and classroom homework: R-help is not intended for these." If you have a specific question on R coding, do ask it (and provide reproducible code). But you should not expect for people on the list to do your homework for you. That is a big no-no. Cheers, Julian Epselon wrote:> I have three problems I am trying to simulate, that I am having difficulty > getting around with. > > Problem 1. > I want to determine the 85 percentile (the x value for which the sum of > probabilities becomes 0.85) of the following distributions (two binomials > and a Poisson with rate Lmbda= np of the two binomials): X ~B(10, 0.3), > Y~P(3) , > Z~B(30, 0.1). I want to show that that Y is a good approximation for Z but > not for X...(by examining these distributions for few > different percentiles) > > Problem 2: > For a binomial distribution X ~ B(20, 0.4), I want to use R to calculate > P{|X ? ?| < 2} and verify that it is near or larger than 0.95. (Hint from > the text book: Since ? = 8 and 2.3 then you may want to read the > weights, or probabilities, of the values 6:10, into a vector v and then use > the command sum(v) to > calculate the sum.) Repeat this for another set of parameters of your > choice. > > Problem 3: > Draw a sample of size 10, from a Poisson with Lambda= 5, and calculate the > mean and the standard deviation of this sample, Repeat this calculation with > size 20 and 30 and demonstrate > that ?X gets closer to ? as the sample size increases. > > Thanks. > > I would appreciate it if someone accompanied the codes with a brief > explanation so I can be able to replicate it myself.
I am a newbie to R and Bio emails and It is clear that newbies make "mistakes", I made several which were pointed out and I am trying to fix them, and as I fix one I make another, in time perhaps I will "know it all", but if it is like surgery, I will make mistakes until I retire But the response of the "old-timers" to these mistakes seems arrogant and cruel and "off putting" and does NOT encourage more participation. In fact it takes "real stuff" to continue after this putdown and that putdown. There are 3,783 links to posting guidelines, which took 1.5 hours to find and read and understand. Why not a link on how the mistakes of the newbies will be dealt with? Or a kindly response from the moderator personal to the newbie rather than to the entire world? Or a kindly general response as from Ben Bolker to my last infraction which was "You might have better luck with this on the Bioconductor mailing list ..." Rather than to the universe... "Using the wrong list: this is for R-sig-mac, and the topic occcurred there recently." All in an effort to encourage promote useful and increasing exchange participation Or not.... Loren Engrav, MD Univ Washington> From: Julian Burgos <jmburgos at u.washington.edu> > Date: Mon, 19 Nov 2007 10:44:49 -0800 > To: Epselon <jazzyazza at hotmail.com> > Cc: <r-help at r-project.org> > Subject: Re: [R] Trying to get around R > > Hello Epselon (if that is your name),This sounds like homework questions.> From the R-help posting guide:"Basic statistics and classroom homework:> R-help is not intended forthese." If you have a specific question on R> coding, do ask it (and providereproducible code). But you should not expect> for people on the list todo your homework for you. That is a big> no-no.Cheers, Julian> >> Epselon wrote: > I have three problems I am trying to >> simulate, that I am having difficulty > getting around with. > > Problem 1. >> > I want to determine the 85 percentile (the x value for which the sum of > >> probabilities becomes 0.85) of the following distributions (two binomials > >> and a Poisson with rate Lmbda= np of the two binomials): X ~B(10, 0.3), > >> Y~P(3) , > Z~B(30, 0.1). I want to show that that Y is a good approximation >> for Z but > not for X...(by examining these distributions for few > different >> percentiles) > > Problem 2: > For a binomial distribution X ~ B(20, 0.4), I >> want to use R to calculate > P{|X - ?| < 2} and verify that it is near or >> larger than 0.95. (Hint from > the text book: Since ? = 8 and 2.3 then >> you >> may want to read the > weights, or probabilities, of the values 6:10, into a >> vector v and then use > the command sum(v) to > calculate the sum.) Repeat >> this for another set of parameters of your > choice. > > Problem 3: > Draw a >> sample of size 10, from a Poisson with Lambda= 5, and calculate the > mean >> and >> the standard deviation of this sample, Repeat this calculation with > size 20 >> and 30 and demonstrate > that ?X gets closer to ? as the sample size >> increases. > > Thanks. > > I would appreciate it if someone accompanied the >> codes with a brief > explanation so I can be able to replicate it >> myself.______________________________________________ R-help at r-project.org>> mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the>> posting guide http://www.R-project.org/posting-guide.htmland provide>> commented, minimal, self-contained, reproducible code.