26: Resampling methods (bootstrapping)

Рет қаралды 146,303

Күн бұрын

Bootstrapping to estimate parameters (e.g., confidence intervals) for single samples. Balanced bootstrapping for inherent biased parameters.

Пікірлер: 36

@marciofernandes7091 7 жыл бұрын

the only good straight foward, video on bootstrapping out there. No book-canned stratified answer, as it is so often common in statistics. Thank you, this video is a piece of art.

@deepanshhh 4 жыл бұрын

There's a very nice video which has come out recently regarding bootstrapping which clearly explains it. kzfaq.info/get/bejne/n9l1lsqgqNPQf2Q.html

@ltbd78 5 жыл бұрын

I learned more in this 10 minute video than I did in my 3 hour lecture.

@drpindoria 4 жыл бұрын

Matthew, this is very nice video with clear elucidation of bootstrapping. Thanks you for sharing.

@yaweli2968 3 жыл бұрын

You do a good job at explaining this. I never thought of plotting the sample means from 1to 10000 or more in R.

@dunslax3 4 жыл бұрын

You're a hero. This video taught me more about bootstrapping than several hours of lectures.

@timmori2811 3 жыл бұрын

Great and concise explanation, thank you! Just what I needed to understand what my prof. wanted me to do and why!

@merumomo 7 жыл бұрын

Well explained in a simple way. Thank you!

@kingasuba709 5 жыл бұрын

this is so helpful, thank you !

@davidbenkert3413 5 жыл бұрын

Thank you so much for this video.

@ferdinandoinsalata3949 7 жыл бұрын

Thanks, nice video of a very useful series. Just a doubt : at the end you say that a way to correct the biased estimation of the variance is to add a quantity to each value. But this does not change the variance ... Could you elaborate on the last part of the video about balanced bootstrap?

@SPORTSCIENCEps 3 жыл бұрын

Thank you for the explanation!

@mcdonalds1499 3 жыл бұрын

wow you are a lifesaver

@SNPolka56 5 жыл бұрын

Great presentation. I thought you were going to construct 95% CI for R2.

@andreneves6064 6 жыл бұрын

Please, some material about gibbs sampling? I need it so much.

@jjoshua95 7 жыл бұрын

if we want the resampling mean value to be greater than then how to proceed

@aimeekeith4280 7 жыл бұрын

THANK YOU!!

@jovandjoe4082 5 жыл бұрын

what does resampling the data with replacement means??

@lemyul 4 жыл бұрын

ty pham

@sassora 4 жыл бұрын

Great presentation. One thing that’s bothering me is that the 95% CI is constructed so that the CIs 95% of the time contain the true parameter value. As said on one slide. The next slide shows 95% of sample means not of CIs. I imagine this holds true but it is not addressed. Would be good to get confirmation.

@meribel7071 5 жыл бұрын

how to do bootstrapping with gretl please?

@panagiotiskioulepoglou3635 3 жыл бұрын

100,000th viewer! Thank you

@charliekrajewski3646 7 жыл бұрын

First off, excellent vid. My question is - and I hope I state it clearly: Is balancing the bootstrap necessary? Can't it be assumed that an obvious outlier in a small data set is an anomaly, and the fact that the resampling doesn't pick it up as often means that it is "correcting" the data?

@vulnvuln 5 жыл бұрын

It hurts me to start with it depends, but it depends. Maybe you're thinking of outliers in a normal distribution, like the one in the video, but that's not what always happens. If you check your data and you see that the bootstrapped standard deviation is the same as the one in the original data without considering outliers (which you know are data points that were incorrectly measured FOR SURE, for example) you can think of it as correcting the data. But you could just have data where some data points are more prone to be picked up than others like height for male and female, in a dataset with more males. There is a chance you'd have even more males, which means bigger values in a higher frequency, and that would bias your dispersion metrics.

@get1up2and3dance 5 жыл бұрын

about the balancing part: we compute the bootstrap mean, then we subtract the difference between bootstrap mean and sample mean and get... sample mean. why not use sample mean from the beginning?

@jainicz 5 жыл бұрын

I believe bootstrap method is primarily used to understand the spread or confidence interval of the data. Based on my limited experience, most data when you bootstrap it, the mean will eventually converge to the sample mean. So when it doesn't, it implies that our initial sample might be inherently biased, or we probably need to repeat the bootstrapping procedures more until the result stabilize. Either case, the presenter offers us one simple way to possibly correct for the bias.

@daducky411 4 жыл бұрын

re adjusing a BS parameter to counter bias , a question arises. Why BS if you are going to end up with same adjusted parameter value as the observed value by adding back the difference between the obs sample's paraemter g variance eg say var_obs =0.15 and the bs parameter eg variance var_bs=0.1. Adding back the difference will simply adjust the bs value to the sample parameter value.

@xico749 2 жыл бұрын

the added value is the sample parameter value (i.e. var_obs) + MEAN of var_bs. Mean of var_bs is not equal to var_bs

@xruan6582 3 жыл бұрын

6:57 I think R² has a standard formula for 95% CI

@user-wi5sl2vg6c 2 жыл бұрын

كيف اترجم الفديو للعربية؟

@rebecabuttner 3 жыл бұрын

Here you can play with the topic more visual seeing-theory.brown.edu/frequentist-inference/es.html#section3

@hanronghu4065 3 жыл бұрын

honoured to be the 1000 one click like

@TooManyPBJs 3 жыл бұрын

You never added why you would want to do balanced bootstrapping. It is to get better performance statistics.

@xico749 2 жыл бұрын

the previous slide showed an example in which the bootstrapped estimator for variance is biased. Balanced bootstrapping removes or at least decreases that bias.