> On Dec 7, 2017, at 2:51 PM, Stephanie Tsalwa <

[hidden email]> wrote:

>

> Assuming the days of raining during half a year of all states(provinces) of a country is normally distributed (mean=�, standard deviation=�) with sigma (�) equals to 2. We now have 10 data points here: 26.64, 30.65, 31.27, 33.04, 32.56, 29.10, 28.96, 26.44, 27.76, 32.27. Try to get the 95% level of CI for �, using parametric Bootstrap method with bootstrap size B=8000.

This has the definite appearance of a homework assignment. It also has several other features which likewise suggest a failure to read the Posting Guide, a link to which is at the bottom of every posting sent out from the Rhelp mail-server.

You are advised to post credential/affiliation information and more context of the wider goals if my assumption of HW-status is incorrect.

--

David.

(And yes I do realize that I am also not posting any affiliation information, either, but I'm retired and am not asking for free advice, am I? Don't follow my bad example.)

>

> my code - what am i doing wrong

>

> #set sample size n, bootstrap size B

> n = 10

> b = 8000

>

>

> set a vector of days of rain into "drain"

> drain = c(26.64, 30.65, 31.27, 33.04, 32.56, 29.10, 28.96, 26.44, 27.76, 32.27)

>

> #calculate mean of the sample for days of rain

> mdr=mean(drain)

> mdr

>

> #calculate the parameter of the exponential distribution

> lambdahat = 1.0/mdr

> lambdahat

>

> #draw the bootstrap sample from Exponential

> x = rexp(n*b, lambdahat)

> x

>

> bootstrapsample = matrix(x, nrow=n, ncol=b)

> bootstrapsample

>

> # Compute the bootstrap lambdastar

> lambdastar = 1.0/colMeans(bootstrapsample)

> lambdastar

>

> # Compute the differences

> deltastar = lambdastar - lambdahat

> deltastar

>

> # Find the 0.05 and 0.95 quantile for deltastar

> d = quantile(deltastar, c(0.05,0.95))

> d

>

> # Calculate the 95% confidence interval for lambda.

> ci = lambdahat - c(d[2], d[1])

> ci

>

>

> [[alternative HTML version deleted]]

>

> ______________________________________________

>

[hidden email] mailing list -- To UNSUBSCRIBE and more, see

>

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.

David Winsemius

Alameda, CA, USA

'Any technology distinguishable from magic is insufficiently advanced.' -Gehm's Corollary to Clarke's Third Law

______________________________________________

[hidden email] mailing list -- To UNSUBSCRIBE and more, see

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.