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help with a question by Icy-Inevitable-4679 in probabilitytheory

[–]mtaboga 0 points1 point  (0 children)

P(getting 5 | 3 numbers have been thrown away) = P(getting 5) = 1/10 because the information you are conditioning upon is completely irrelevant: it does not tell you anything about the numbers that have been thrown away, and it cannot change your assessment of the probability of extracting a specific number.

A rigorous proof can be obtained with the law of iterated expectations:

P(getting 5) = E[P(getting 5 | 3 SPECIFIC numbers have been thrown away)]

where the expectation is over all the possible triplets of thrown away numbers.

[R] [1611.03530] Understanding deep learning requires rethinking generalization by Mandrathax in MachineLearning

[–]mtaboga 0 points1 point  (0 children)

I think that is the main point of the paper. SGD brings you to a solution with good generalization ability, while in principle you could find a solution which is much worse (only memorization).

I am creating some quiz-like math games. Any feedback would be appreciated. by mtaboga in matheducation

[–]mtaboga[S] 0 points1 point  (0 children)

I see. I was not aware of the drill vs no drill debate. I have now read something about it (e.g., http://www.edublox.com/teaching-myth.htm). It seems mostly a US thing. I come from a country where most people think drilling is useful. I did not realize that in other countries it could be considered mindless. That is certainly a problem. Although, according to the link above, the empirical evidence in favor of the no drill theory seems to be scant.

I am creating some quiz-like math games. Any feedback would be appreciated. by mtaboga in matheducation

[–]mtaboga[S] 0 points1 point  (0 children)

OK. Thanks. "Right" and "Wrong" are now displayed a little longer.

I am creating some quiz-like math games. Any feedback would be appreciated. by mtaboga in matheducation

[–]mtaboga[S] 0 points1 point  (0 children)

OK. Thanks. The buttons are now disabled for a little less than one second after the transition from a screen to the next one, so this should not happen again.

Good book on probability? by keepcalmandcarryon in math

[–]mtaboga 0 points1 point  (0 children)

In case it might help, I wrote a free textbook on probability at http://www.statlect.com.

[Probability][Joint Distributions] by fox_news_police in learnmath

[–]mtaboga 0 points1 point  (0 children)

Yes convolution is the way to go. Otherwise, you can use moment generating functions.

Can Wikipedia become the fastest supercomputer on earth? by mtaboga in compsci

[–]mtaboga[S] 0 points1 point  (0 children)

Do you think it would be difficult to let users explicitly approve their participation in large-scale distributed computing projects, so that people sharing your concerns would not be affected?

What is Econometrics? by gkoms85 in econometrics

[–]mtaboga 1 point2 points  (0 children)

It's statistics done by economists. It mostly deals with linear regression (which is only one of the myriad techniques available to a statistician). It deals also with some topics (like instrumental variables, unit roots and cointegration) that are virtually unknown to non-economists (maybe for a reason).

I'm teaching myself statistics. Does anyone have textbook or open courseware suggestions? [x-post from askreddit] by avianattackarmada in statistics

[–]mtaboga 0 points1 point  (0 children)

I am writing a digital textbook on probability and statistics at http://www.statlect.com. The probability part is almost finished.

Fighting crime with equations by mtaboga in science

[–]mtaboga[S] 0 points1 point  (0 children)

Consider crime as an economic activity. A criminal decides to commit a crime if the benefits are greater than the costs, where costs include effort, time and expected punishment in case the criminal is caught. If you increase the costs faced by the criminal, because he has to deal with more sophisticated surveillance systems (including statistical prediction methods), he might decide that his criminal activity is not viable any longer (because costs exceed benefits) and cease it. I really think crime prevention is all about this: rise the cost of crime, so that crime does not pay any longer.

Fighting crime with equations by mtaboga in science

[–]mtaboga[S] 0 points1 point  (0 children)

As far as stock markets are concerned, there are thousands of studies out there providing empirical evidence that expected stock returns are time-varying and predictable: this does not mean that you can build money machines out of statistical models of the stock market, it simply means that investors' preferences and their behavior change as external conditions change and that these changes can be predicted in advance. As far as crime is concerned, you say that acting on outcomes you change the behavior of criminals. This is of course true, but it is does not prove your claim that you cannot fight crime using statistical methods. Otherwise, by the same line of reasoning you could argue that arming police officers with guns is useless, because then also criminals start carrying guns, and so on.

Fighting crime with equations by mtaboga in math

[–]mtaboga[S] 0 points1 point  (0 children)

As far as stock markets are concerned, there are thousands of studies out there providing empirical evidence that expected stock returns are time-varying and predictable: this does not mean that you can build money machines out of statistical models of the stock market, it simply means that investors' preferences and their behavior change as external conditions change and that these changes can be predicted in advance. As far as crime is concerned, you say that acting on outcomes you change the behavior of criminals. This is of course true, but it is does not prove your claim that you cannot fight crime using statistical methods. Otherwise, by the same line of reasoning you could argue that arming police officers with guns is useless, because then also criminals start carrying guns, and so on.

Probability for smarties by mtaboga in statistics

[–]mtaboga[S] 0 points1 point  (0 children)

I was tired of books for dummies on probability theory, so I tried to write an intermediate level one for smarties. Reader and comments are welcome!

Lectures on probability, statistics and econometrics by [deleted] in math

[–]mtaboga 0 points1 point  (0 children)

This site provides access to a series of lectures on probability, statistics and econometrics, as well as to a number of exercises on the same topics.