My statistics exam

I send this to my professor 3 days ago, he hasn't replied. d-does this mean I am wrong and made a total f-fool of myself?

I don't think I'm wrong but people who are wrong usually don't

Other urls found in this thread:

youtube.com/watch?v=mkDzmI7YOx0
twitter.com/AnonBabble

here's my proof

If there isnt information you didnt present here, I think you dun goofed.

The underlined sentence is given you as crucial information in order to solve the tasks. For all intenses and purposes it is absolutely arbitary and I dont even know how you concluded it should say something else

that's all there is..

but do you see my working?

20% are overbooked, 25% are late, so this means that 5%chance that a flight is overbooked and late since 0.2x0.25=0.05 and 15% of flights are overbooked and depart on time since 0.20x0.75=0.15

what I'm trying to say, it's impossible to be 60% if the two values 20%,25% are given

youtube.com/watch?v=mkDzmI7YOx0

it's statistics 101

But you dont know how much the two sets overlap. Thats what the underlined sentence is supposed to tell you.

20% (of all) are overbooked and 75%(of all) depart on time. It would be absolutely possible for 100% of the overbooked flights to depart on time.

there's nothing impossible about the underlined sentence. i think you need to take statistics again

No, you're wrong wrong wrong. You're assuming that the probability of a flight being late is completely independent from the probability of the flight being overbooked, when you have no reason to assume that. In fact, what the professor was hinting at was that they are NOT independent, and that there is some skewing, which you were supposed to evaluate in the problem.

Jeez, I'm not even a math person and even I can see that. I mean, it IS Statistics 101, but you haven't finished Statistics 101 yet and you're talking like you've got it all figured out!

yeah I failed the exam that one was the resit and I failed it too probably

Dude you just need to practice. I'm really dumb and distractable and I got an A in stats by leaving my cell phone at home and going to the library to study away from the computer every week.

If I was your prof, I wouldn't respond because of the douchey last sentence in your email.

I still believe that I am right

but it always has to be 100%
20% are overbooked
80% are not overbooked

25% are late
75% are not not late

to get how much of the 20% overbooked flights are late you simple multiply it,
0.20x0.25= 5% = Oberbooked AND late
0.20x0.75=15% =Overbooked AND NOT LATE

and the same for not overbooked flights:

0.80x0.25= 20%
0.80x0.75= 60%

and all the numbers add up to 100% which it supposed to!

you guys are not listening and simply assume that I'm a dumb ass

and isnt it a coincident that after my calculation 60% of the none overbooked flights are not late? coincident? i dont think so

That email is so unprofessional. Please read up on email etiquette.

You're still wrong. Stop being a douche and read the other comments thoroughly.

>I still believe that I am right
you're not

>to get how much of the 20% overbooked flights are late you simple multiply it,
only if the conditions of overbooked and late are independent of each other, which they have been explicitly state in the question to not be

I'm still not over the fact that I never had to study in school and now in uni it's all about looking at past exam papers and prepairing for it and not actually learning

but the :) totally saves it dude

you do know that etiquette is dead, millenials killed it

show me the proof because youre just being presumptuous, your explanation doesnt make statistical sense, I showed you my workings that show 25% of all flights are being late where 5% are of overbooked flights and 20% of none overbooked flights and In my working the 60% even pops up, that's just coincidence right? bulllshit

Of course the numbers add up to 100%, because you just went in a circle. That doesn't mean that that's the only possible way to have 20% overbooked, 80% not overbooked, 25% late, and 75% not late.

Like
said, there are other possible combinations than the one you're proposing, once we remove the assumption of independence of events (which is what your professor is asking you to do.)

>and now in uni it's all about looking at past exam papers and prepairing for it and not actually learning
>not actually learning

Maybe you would have actually learned something if you had adequately prepared for this exam by looking at past exam papers and working the problems out until they clicked...

...

Did you even read my reply? Or did you just totally miss the point of it?

"booked" and "late" are both subsets of the same set "flights" and you dont know how much they overlap. Thats what the underlined sentence is about.

i) 67%
ii) 12%
b) 13%
My question is why it asks b) before a)

Here's the proofs.

There are living 100 people in my house. 20% of them are female and 25% of all people are blonde.

There is a 60% chance of a female not being blonde.

Does this make more sense to you?

Let's assume there are 100 flights and fit. We'll say 20 flights are overbooked and 12 of those 20 flights are also late. We will then say that say that 13 of the non overbooked flights are also late.

We now have 25 late flight so 25% late.

We have 12 overbooked and late which is 60% overbooked and late.

And we assumed 20 of the 100 flights are booked 20% overbooked.

The profs numbers make sense in this sample. You can generalize that to n flights and show it makes sense for almost any number of flights.

Meant to say 60% of overbooked flights are late.

jesus, I'm trying to understand.

im computing here

thanks for the answers

>"haha, Bayes' Rule? More like Gayes' Rule! I don't need to study dat shit!"
>"What do you mean I failed? But I'm a genius!"

goddamn are all current college students this arrogant, bull headed, and lazy. You're not emailing your friend it's your prof and you're accusing him of screwing up, so don't talk like an ass. Especially since you fucking failed your exam and apparently the resit. Also learn how to study.

P(not late | overbooked) = 0.6
P(overbooked) = 0.2
P(not overbooked) = 0.8
P(late) = 0.25
P(not late) = 0.75

law of total probability, P(A) = [math]\Sigma{} P(A|c)P(c)[/math]
Bayes theorem: [math]P(B|A) = \frac{P(A|B)P(B)}{P(A)}[/math]

1.
P(not late) = P(not late | overbooked)P(overbooked) + P(not late | not overbooked)P(not overbooked)
0.75 = 0.6*0.2 + P(not late | not overbooked)*0.8
P(not late | not overbooked) = [math]\frac{0.75 - 0.6*0.2}{0.8} = 0.7875 [/math]

2.
P(late) = P(late | overbooked)P(overbooked) + P(late | not overbooked)P(not overbooked)
0.25 = P(late|overbooked)*0.2 + P(late|not overbooked)*0.8
P(late|overbooked) = P(overbooked|late)P(late)/P(overbooked)
P(late) = P(overbooked|late)P(late)/P(overbooked)*P(overbooked) + P(late|not overbooked)P(not overbooked)
P(late) = P(overbooked|late)P(late)+P(late|not overbooked)P(not overbooked)
P(late|not overbooked) = (P(late)-P(overbooked|late)P(late)) / P(not overbooked)
P(late|not overbooked) = (0.25 - P(overbooked|late)*0.25)/0.8
See problem 3 for P(overbooked|late)
P(late|not overbooked) = \frac{0.25 - 0.32*0.25}{0.8} = 0.2125 [/math]

3.
P(overbooked) = P(overbooked|late)P(late)+P(overbooked|not late)P(not late)
P(overbooked|not late) = P(not late|overbooked)*P(overbooked)/P(not late)
P(overbooked) = P(overbooked|late)P(late)+ P(not late|overbooked)*P(overbooked)
P(overbooked|late) = (P(overbooked) - P(not late|overbooked)P(overbooked) ) / P(late)
P(overbooked|late) = (0.2 - P(not late|overbooked)*0.2) / 0.25
P(not late|overbooked) given to be 0.6 in prompt.
P(overbooked|late) = [math]\frac{0.2-0.2*0.6}{0.25} = 0.32[/math]

>P(late|not overbooked) = \frac{0.25 - 0.32*0.25}{0.8} = 0.2125 [/math]
bah, that should be
P(late|not overbooked) = [math] \frac{0.25 - 0.32*0.25}{0.8} = 0.2125 [/math]

so basically I should have used Bayes theorem and not my gay little trees of pleasure

feels humbling, should I apologize to my prof?

You're a retard. First of all, your email is completely unprofessional. Also, you underline the word "none" when it clearly makes no grammatical sense in that sentence, making you look even more retarded.

Lastly, the answer is stupidly simple:

20% of flights are overbooked.
60% of those (or .2*.6 = 12%) are late
25% of all flights are late

It's not hard to figure out from there.

But now you look like an asshole, since you said "I discovered a crucial mistake", took a picture of a test question, and emailed it to your professor. I'm hoping this was some kind of take-home exam, because most professors will report you for using your phone during a test, especially to take pictures of the test.

Yes, you probably should apologize.

...

...

Yes. You absolutely should.

hey OP did you send that stupid tree to your professor

how's it feel knowing you sent pictures of dicks to your teacher

they probably haven't gotten back to you because they're writing you up

holy shit this had better be fake because this is one of the most embarassing things i can imagine

fuckkk

Hopefully you can turn this into a formative experience.

the dicks were for you asshats

(OP)
OP, if I were your professor, I'd ignore/delete the email based on the spelling and grammar alone.
You're either too stupid for college, or you didn't put any effort into the email.
Either way, message deleted.


>I should have used Bayes theorem and not my gay little trees of pleasure
No, the problem is your trees branches shouldn't assume a 25/75 split at the second level of each main branch.

>60% of those (or .2*.6 = 12%) are late
should be:
60% of those (or .2*.6 = 12%) are *on time*

That's an awful lot of math for what I'm pretty sure are the wrong answers.

Let me try, assume 100 total flights:
20 flights are overbooked
....60% of these are on time (12 flights)
....40% of these are late (8 flights)
80 flights are not overbooked
....we still need 17 more late flights, so 17 of the 80 are late
....and 63 are on time

answer (ai): 63
answer (aii): 17
answer b: 32%

both your math is off
is right

>That's an awful lot of math for what I'm pretty sure are the wrong answers.
Nope. You're providing counts, not probabilities. The prompt asked for probabilities.
>63 flights / 80 flights = 0.7875
>17 flights / 80 flights = 0.2125

Or wait no. Your answers are right if the prompt was meant to ask "What proportion of all total flights meet this criteria", while my answer is right if the prompt was meant to ask "What is the conditional probability for this given sub-case".

>The prompt asked for probabilities.
OK, I left the percent sign off, should have been:

answer (ai): 63%
answer (aii): 17%
answer b: 32%

flights / 80 flights = 0.7875
Question ai doesn't ask for percentage of non-overbooked flights that are on time.
It want's to know what percentage of flights are "neither late nor overbooked".
And sure, "late but not overbooked" are 21.25% of non-overbooked flights, but they're 17% of total flights.

to end on a high note, I lost 9marks because of this so I failed the resit exam too

thanks for enlightening me guys I hope you rot in hell

>I would gladly accept to pass this module based on me pointing this out :)
Eat shit you fucking retard oh my god

>I hope you rot in hell
Maybe you should have gone to trade school and become a plumber.
...or you could just insult the people who found the flaw in your reasoning after you asked them to check your math.

don't take it personal nerd it was meant to be a joke, I am honestly thankful to you

Get owned oh my god Allahu ackbar

Two questions:

1. Is English your first language?
2. Are you studying in an English-speaking country?

I'm trilingual, I currently study in England.

you don't like my apology letter?

>you don't like my apology letter?
Not him but...
You've got what should be 3-4 sentences in there, as one long, run-on sentence.

>|

Did you grow up in an English-speaking environment?

Also I didn't see that apology letter. You really need to take a class in writing emails. Any email to a senior should begin simply with "Dear Mr./Ms./Dr./Prof. so-and-so". You also used a really long run-on sentence: your entire email is a single sentence. This is generally frowned upon in writing. "none overbooked" should really be "non-overbooked", you made this error in your first email as well. In addition, "it was me" should be "it was I", since the pronoun follows a linking verb. For that matter, you should simply say "I had used a wrong formula", which uses the preferred active voice. Your whole email should also begin with an apology for the last email, since that's what you're writing this email for.

>statistics exam
>"chance"
Professor is a quack.

nah I didnt,

I agree with you an all of these, but I literally wrote it in one thought without even thinking about reading it.

I don't get why you're all so anal about stuff he is literally like a waitress to me, an overpaid 35k shekels a year waitress.
It's not like I'm writign a letter to someone I respect

like right now for example haha

>I don't get why you're all so anal about stuff he is literally like a waitress to me, an overpaid 35k shekels a year waitress.
that's why you failed user

What a great attitude to life.

what uni u at

>he is literally like a waitress to me, an overpaid 35k shekels a year waitress.
A waitress with 12 years of study who is probably tenured and an active researcher? Okay.

you're literally a human trashcan, please go kill yourself

And you're just a shitty customer getting him paid. You are meaningless trash to him; he doesn't even know you exist, and if he does, he will forget about you within a year. He is a prof that you will remember having forever. You're just a worthless piece of shit.

You are an idiot, Karl.

Your email is confusing due to the grammatical errors. And you shouldn't tell your professor that you would accept a reward. He is your superior- treat him that way.

Fuck off. You should probably stop being a dumbass.

obvious fake Karl, typing too immaculate

wow you guys do get butthurt when someone insults academia

I guess thats what happens when you insult an echo-chamber

also not Karl but the K and L is correct

Janitor delete this thread it's against the rules for homework help

>when someone insults academia
no, when someone acts like a shithead to someone else

Whatever you say, not Karl ;)

And it's not about academia. It's about you being a dick. I'd still tell you to fuck off if you acted that way to any person giving there time up for you.

Their* time. Sorry, I totally Karl'd my grammar.

>I guess thats what happens when you insult an echo-chamber
like /pol/, where you came from?

we create the world of tomorrow, what do you do?

he's trying to destroy it

>/pol/
>creating anything but more cumrags

Stay behind the wall little man. Keep your tears to yourself.

Lick my asshole for $10
Pics for $5

Looks like you're pretty butthurt that I insulted your echo chamber.

Karl, /pol/ is the next stop for newfags after they've graduated from /b/.

lmFAO this isn't even about insulting academia, you're just a little shithead who doesn't know his place in this world. quit acting like you're such a great fucking person when you're just a stale cumrag who thinks he's the best when in reality you're just a dumbass who will never amount to anything great.

Zeitgeist kissed us glory you and your false god "science" and the circle jerk you peseudointellectuals call academia

I thanked for the people that enlightend me about that I used a wrong formula for a shitty problem but you kept attacking, you know why? cause ya'all a bunch of effeminate cucks and when you smell testosterone you get scared and become the glorious keyboard heros you pretend to be in this thread

once again thanks for the people who showed me something new and I'm out since frankly I don't give a damn about estrogenic girly man like you

Ssshhh go stay in your loser corner with Bernie sad little man.

>OP is an idiot who can't into babby statistics
>OP confirms that he is from /pol/
hmm really makes you think...

hahahahah he actually thinks "cuck" is a legitimate insult, get a load of this guy

Karl that was a tenth grade math problem.

still butthurt lmao. let me know when you get highschool education. protip : you can't get it from tumblr ;)

Here's your (You).

Now please go back to your shitty /pol/ and stay there for the remainder of your lifespan, retard.

Seriouslt /b/ -> /pol/ -> /tv/ or /v/ -> other fastish boards like /mu/ -> everything else

Build that wall, and stay behind it loser crybabies.

Mate you're the one who got a 10th grade maths problem wrong, acted all high and mighty about it to your fucking PROFESSOR, and when called out on it, got all defensive and started insulting everyone around you. I think you're the one in need of an education here.

Shit, the jig is up.

"Loser crybabies"
-Karl

which karl ?

wow
let this thread die

Original OP here. I'm not sure why people are pretending to be me. It's not very fun being me.

Just wanted to clear a few things up:

(1) Yes, my name is Karl. I was named after the fat beta kid on Jimmy Neutron.

(2) I've offered my tenth grade math teacher a lovely "reconciliation blowjob" to make amends.

You brought this on yourself, Karl

This thread is horrible

>(2) I've offered my tenth grade math teacher a lovely "reconciliation blowjob" to make amends.
pics or it didn't happen

> Giving your prof evidence that you used a phone in your exam
> "I'd gladly accept a pass :)"

you're an idiot and deserve to fail

>I found a thing, p-p-please let me pass

/thread

holy fuckballs you're retarded
no wonder you're begging for ways to pass the module

you should read his apology letter here and this gem of his here