Abandoned Forum

[Bomadeno]

How is your keyboard laid out? I recently discovered various european keyboards to be quite different. The shift keys of my numbers are !"£$%^&*()

I can understand some keyboards having support directly for 'unusual' characters, tub is it necessary to change the position of all teh symbols around? Do some nations use less brackets?

[Pimienta]

the only difference between yours and mine is the 3
3=#
however there are a lot of different bracket keys like: {} [] () but for a math problem all of those brackets can be used though I don't know how they'd be used in actual typing

[Bomadeno]

They're used a lot in programming, so I like them where they are (to the right of the letters for me)

They're useful things there, but in text I only use (), and occasionally []. I can't really understand maths problesm, which is sad, because half my course is based on maths. It just takes me a really long time to understand things. I need to start revising soon really. Don't suppose anyone knows anything about Bayes do they?

[Pimienta]

I googled it and it's a bit beyond my level I think

[Bomadeno]

Alas, it is beyond mine too. Once I understand it, maybe i'll try to explain in some useful way. The internet can really suck at explaining some things.

[Pimienta]

yeah the internet isn't all that great with explaining

[lifeis42]

The enternet nor most humans thats why i come here

[lifeis42]

i dont much understand bayes but i seem to recall hereing it once on the tv show numbers

Now i kind get it this a realy good example

Example 1: Drug testing
Bayes' theorem is useful in evaluating the result of drug tests. Suppose a certain drug test is 99% sensitive and 99% specific, that is, the test will correctly identify a drug user as testing positive 99% of the time, and will correctly identify a non-user as testing negative 99% of the time. This would seem to be a relatively accurate test, but Bayes' theorem will reveal a potential flaw. Let's assume a corporation decides to test its employees for opium use, and 0.5% of the employees use the drug. We want to know the probability that, given a positive drug test, an employee is actually a drug user. Let "D" be the event of being a drug user and "N" indicate being a non-user. Let "+" be the event of a positive drug test. We need to know the following:

P(D), or the probability that the employee is a drug user, regardless of any other information. This is 0.005, since 0.5% of the employees are drug users. This is the prior probability of D.
P(N), or the probability that the employee is not a drug user. This is 1 − P(D), or 0.995.
P(+|D), or the probability that the test is positive, given that the employee is a drug user. This is 0.99, since the test is 99% accurate.
P(+|N), or the probability that the test is positive, given that the employee is not a drug user. This is 0.01, since the test will produce a false positive for 1% of non-users.
P(+), or the probability of a positive test event, regardless of other information. This is 0.0149 or 1.49%, which is found by adding the probability that a true positive result will appear (= 99% x 0.5% = 0.495%) plus the probability that a false positive will appear (= 1% x 99.5% = 0.995%). This is the prior probability of +.
Given this information, we can compute the posterior probability P(D|+) of an employee who tested positive actually being a drug user:


Despite the apparently high accuracy of the test, the probability that an employee who tested positive actually did use drugs is only about 33%, so it is actually more likely that the employee is not a drug user. The rarer the condition for which we are testing, the greater the percentage of positive tests that will be false positives.


It can also applie to the monty hall problem the three diffrent colored door one and theres a prize behind one and the host opens one of the ones you don,t chose then gives you the option to pick agian

[Bomadeno]

That is a good explanation, I agree. I get it now, (though god forbid if they put it on another exam) it's quite a useful technique. I never thought of applying it to the monty hall problem! I love that problem... (not that I understand it, it's just cool)

[Mysti]

the keyboard on my Eee pc used to be the default UK English standard, but now for no reason i can think of, apart from that the pc has a mind of its own and 'wants to make life more difficult, the @ sign has become Shift+2, the bracket is where the hash is supposed to be, the | is where the squiggly line thing is supposed to be, the quotation marks don't work anymore and when you press it either nothing happens or occasionally if you hammer the key down hard enough you get these really tiny quotation marks (¨) which i am not sure are quotation marks at all. The hash key is Shift+3 where my pound sign is supposed to be, Shift+6 doesn't do anything so i cant use Japanese-type emoticons unless I cope and paste them. I am fairly sure it is the European settings as I have such characters as é, ü, ú, í, ó, ö, á, ñ, ¿, æ etc upon pressing Alt Gr.

[Bomadeno]

http://www.lornajane.net/posts/2008/Debian-Change-Keyboard-Layout

says that you need to put this into your terminal

Code: Select all

dpkg-reconfigure console-data

It looks reasonable to me, as commands go. You should check around first though

[Pimienta]

I don't have the straight down line thingy that all of you have
this thing that I copied from mysti's post"|"

[Bomadeno]

That's odd. It's used in quite a few programming languages, so you'd think it would be somewhere on the keyboard. I used to think I didn't have it but then I found it, mine is shift+\. However if you don't need to do programming or maths, you will probably never need to use it and so you should let it hide in peace.

[Pimienta]

|wow I guess I do have it

yayay I have the weird straight line button

[Bomadeno]

Let us have a party!



Was that a bit of an overreaction? Anyway, congratulations on finding the wired straight line key!