bootstrap

[@user-tn9tw3yk2e]

Hi, Jeff! Would you like to send history.R of your lesson? I need to test it. Thank you!

[@johannyalva4457]

hi! i loved your video , even if my mother tongue is not english i was able to understand a 97% ! i would like to learn inference, and multivariate analysis in R , if u have any videos it could help me a lot!! greetings from italy by a Peruvian girl .lol.

[@u9772212]

Great Video! Thanks :)

[@MouhssineFakhtaoui]

Can you share with us the link to download the PDF ?

[@user-vd8rz8lr2b]

Thank you so much

[@flufy9]

Thanks a lot

[@SNPolka56]

Hi Mr. Leek: Do these sub-samples which are drawn from the sample have smaller size or the same size as the sample?

[@abel.borges]

In R, sample(x, replace=TRUE) returns in a vector of size length(x) (assuming x is a vector) samples of x drawn with replacement. The (default/standard) bootstrap method uses indeed sub-samples with the same size as the original sample.

[@SNPolka56]

Thank you very much. So x need not have the same size as the original sample. It seems the standard option implies making copies of the original data.

[@abel.borges]

I'm glad to help. In practice, if you have some computational constraint, you may use sub-samples of smaller size and adjust the "theory" (variance, confidence intervals etc) accordingly. I see no harm in that. The R code is like sample(x, size=n, replace=TRUE). About your last phrase, I think you mean that the bootstrap (bs) samples contain only values already observed in the original sample, which is true, but the values are re-used as they appear in the original sample (following the observed frequencies of smaller or greater values). Bootstrapping is equivalent to sampling from the distribution which puts 1/n probability mass on each x_i (this is the empirical distribution). It converges strongly with n to the true (unknown) distribution from which the original sample came from. This means that, as n grows, bs is like we were sampling from the true distribution function.

[@Jacob930321]

Is this video from some online course? Great video!

[@juanbilly1364]

I know it is pretty randomly asking but do anybody know of a good site to watch newly released tv shows online ?

[@henryadrien9429]

@Juan Billy i use Flixzone. You can find it on google :)

[@acemoises8991]

@Henry Adrien Yup, I've been watching on flixzone for since march myself :D

[@juanbilly1364]

@Henry Adrien thank you, signed up and it seems like a nice service :) I really appreciate it!!

[@henryadrien9429]

@Juan Billy happy to help :D