Anyway, EMRA32, back to your original question… What level CFA are you? I went on an interview last week for a covered call strategy fund, so they did ask me some options questions such as: 1. What factors into how you price an option? Let’s say a normal call option. How do you determine the price? I basically talked about intrinsic and time value of an option. I think he might’ve even mentioned a third factor but I don’t remember. 2. Do you know the Black-Scholes option pricing method? He was about to ask me questions but I just told him I don’t know. I just became an L2 candidate and have not studied that yet. He moved on. He also asked me non-options related questions such as: 1. What is the difference between time-weighted rate of return and money-weighted rate of return? He asked me this because on my resume I put that I do some performance analysis with modified Dietz, modified IRR, etc. So know your resume inside and out. This is somewhat of a given, but I’ve heard of a lot of people who just put stuff on their resumes that they don’t even really know how to do. All research roles will ask you if you do any investing on your own or what you think about the current markets. I think you pretty much NEED to have a stock pitch ready at all times and be able to explain your past investing experience intelligently. Good luck man.
Search the forums (a few years back) for books like the one referenced here: http://www.amazon.com/Heard-Street-Quantitative-Questions-Interviews/dp/0970055250/ref=sr_1_1?ie=UTF8&s=books&qid=1222361873&sr=8-1
topher Wrote: ------------------------------------------------------- > 2) MFE I think you’re wrong there. It’s actually > .25 because .125 can only capture the ants moving > in one direction. Let’s say they all move > clockwise. Then the probability is .125. You also > have to add in the probability that they all move > counter-clockwise which is another .125. Hence, > total probability is .25. yep i agree.
Just curious, what’s the answer to the gnome question? Man, that is one hell of an elaborate question to be asked in an interview. My guess would be that the gnomes would have the gnome standing in the back say (for his “guess” as to the color of his own hat) whichever color the majority of the gnomes were wearing. But based on how you described the question, it would be impossible to predict how many gnomes would be saved by doing that (at least 5, I suppose). So what gives?
MFE Wrote: ------------------------------------------------------- > 1) Probablity of pre trigger pull is easy 2/6 = > 1/3. > > Let’s randomly place bullets in 1-2 slot. after > first pull and blank that means you are at spot: > 4, 5, 6 or back to 1. this is 1/4 that you die so > i’d take another pull on the trigger. After the first trigger pull you now know that you used up one of your non deadly trigger pulls. When you first spin it is random, so you have 2/6 chance of death. Now you have used up one of your chances so you have 2/5 (worse odds, assuming you want to live). If you give it another spin you randomize the chambers and your chances are once again 2/6. Reminds me of deerhunter.
eureka Wrote: ------------------------------------------------------- > MFE Wrote: > -------------------------------------------------- > ----- > > 1) Probablity of pre trigger pull is easy 2/6 = > > 1/3. > > > > Let’s randomly place bullets in 1-2 slot. > after > > first pull and blank that means you are at > spot: > > 4, 5, 6 or back to 1. this is 1/4 that you die > so > > i’d take another pull on the trigger. > > > After the first trigger pull you now know that you > used up one of your non deadly trigger pulls. > When you first spin it is random, so you have 2/6 > chance of death. Now you have used up one of your > chances so you have 2/5 (worse odds, assuming you > want to live). If you give it another spin you > randomize the chambers and your chances are once > again 2/6. Reminds me of deerhunter. disagree. still think I am right… think about your scenario after you pull the trigger and you live… XX0000 - X is where the bullets are. so after you pull the trigger and you live, then you are at one of the following spaces 1: 1X0111 - and the probability of being at the deadly spot (the first one) is 25%, thus i’d pull the trigger again.
you can save 9 gnomes for sure. gnome #10 will say black or white depending on which color is odd in number. since there are 9 hats in front of him, there has to be an odd and an even black/white hat combination. he will have a 50% chance of living but the rest of them should have enough information to live.
EMRA32 Wrote: ------------------------------------------------------- > What in the hell is this… > > Im looking for real answers and you guys are more > concerned on whats the best way to find 25*36? hahhah
ShouldBeWorking Wrote: ------------------------------------------------------- > you can save 9 gnomes for sure. gnome #10 will > say black or white depending on which color is odd > in number. since there are 9 hats in front of > him, there has to be an odd and an even > black/white hat combination. > > he will have a 50% chance of living but the rest > of them should have enough information to live. Hmm. I’m not sure I agree with/understand this explanation, but I suppose I agree with you about the 9. I mean, basically the gnomes could arrange it so that each gnome would just say the color of the hat of the gnome in front of him. So everyone but the 10th (the last one in the row, the first to pick) will be guaranteed to live, and the 10th just has to hope that his hat is the same color as the one of the 9th gnome.
should be working is correct but not for the reasoning you stated. the answer is: they discuss a strategy. The gnome in the very back counts to see whether there is an even or odd number of black hats. If even, he will say black, if odd, he will say white. He has a 50/50 chance of getting it right. From this, the 9th gnome can deduce the color of his own hat. For example, if the 10th gnome saw an even number of black hats, and the 9th gnome sees an odd number, he knows that his own hat is black. If he sees an even number, he knows his own hat is white. After each “black” is called out, the system switches, as “black” now represents odd and “white” represents even number of black hats. So on and so forth. This ensures a 9/10 survival rate; the 10th gnome has a 50% chance at survival.
Aspiring Analyst Wrote: > Hmm. I’m not sure I agree with/understand this > explanation, but I suppose I agree with you about > the 9. I mean, basically the gnomes could arrange > it so that each gnome would just say the color of > the hat of the gnome in front of him. So everyone > but the 10th (the last one in the row, the first > to pick) will be guaranteed to live, and the 10th > just has to hope that his hat is the same color as > the one of the 9th gnome. what if you’re #8 and #9 just said black. but the gnome in front of you has a white hat on. do you save yourself or do you stick with the strategy?
MFE Wrote: ------------------------------------------------------- > eureka Wrote: > -------------------------------------------------- > ----- > > MFE Wrote: > > > -------------------------------------------------- > > > ----- > > > 1) Probablity of pre trigger pull is easy 2/6 > = > > > 1/3. > > > > > > Let’s randomly place bullets in 1-2 slot. > > after > > > first pull and blank that means you are at > > spot: > > > 4, 5, 6 or back to 1. this is 1/4 that you > die > > so > > > i’d take another pull on the trigger. > > > > > > After the first trigger pull you now know that > you > > used up one of your non deadly trigger pulls. > > When you first spin it is random, so you have > 2/6 > > chance of death. Now you have used up one of > your > > chances so you have 2/5 (worse odds, assuming > you > > want to live). If you give it another spin you > > randomize the chambers and your chances are > once > > again 2/6. Reminds me of deerhunter. > > > disagree. still think I am right… think about > your scenario after you pull the trigger and you > live… > > XX0000 - X is where the bullets are. > > so after you pull the trigger and you live, then > you are at one of the following spaces 1: > > 1X0111 - and the probability of being at the > deadly spot (the first one) is 25%, thus i’d pull > the trigger again. Not to beat an injured horse, but I still disagree. You just have to calculate the probability every time you pull the trigger without spinning, since spinning re-randomizes the chambers. This article agrees with me, but explains it much better than I have: http://library.wolfram.com/infocenter/MathSource/5710/Elementary%20Russian%20Roulette.pdf
jax26 Wrote: ------------------------------------------------------- > 2) Three men (A, B, C) are in a dual, where they > take turns shooting. Person A gets to shoot first, > Person B gets to shoot second, and Person C gets > to shoot third. Person A and C are both amateur > shots; Person A hits his target 1/3 of the time, > person C hits his target 1/2 of the time. Person B > is an expert and hits 100% of the time. Where > should person A first shoot to maximize his > chances of winning the game? Do they all know the skill levels of each other?
for the love of god the gnomes have like 5 minutes to talk about what theyll do in their situation. Heres how i save NINE gnomes with the possibility of 10… thats right folks… NINE guranteed! if the 10th gnome sees a black hat in front, he should shout out whatever answer he wants like WHITE!!! or BLACK!!! if he sees a white hat on the 9th gnome he should speak it softly. “white…” “black…” In this way, the gnome will be alerted that he will be wearing a white or black hat. 9 lives saved. the tenth is really going to sacrifice himself.
> > Not to beat an injured horse, but I still > disagree. You just have to calculate the > probability every time you pull the trigger > without spinning, since spinning re-randomizes the > chambers. This article agrees with me, but > explains it much better than I have: > http://library.wolfram.com/infocenter/MathSource/5 > 710/Elementary%20Russian%20Roulette.pdf let’s revisit: 1. You have a 6 chamber revolver. It’s time to play Russian Roulette. 2 chambers are filled with bullets. They are consecutively placed. You give it a whirl. Fire once. Blank. Now, you can either put it directly to your head and shoot, or you can give it one more spin and then shoot. Which way do you choose and why? ------------------------------------------------------------- the big piece of this puzzle is " They are consecutively placed". If this statement were ommitted then I would agree with you, however I am still inclined to stick to my guns on my first though. (pun intended).
redvolve, yes you know everyones skill level
I do like the shouting/whisper technique as well which would work. Using the color in front of you as a guide, you whisper if it’s the same as your otherwise you scream. Thus if you are the 9th gnome and the 10th gnome sees your color as black. He would whisper black. This starts the chain. The 9th now know his color is black. if the 8th is white, he would scream BLACK! this is tip to the 8th that his color is the opposite of the 9ths.
here’s the better solution (i guess…) ------------------------------------------------------------------------------ http://mathforum.org/library/drmath/view/52224.html Date: 12/11/2001 at 10:08:36 From: Andrew Love Subject: Solution to Gnome puzzle Dear Dr. Math, I checked your pages out yesterday as I do periodically, and noticed that you didn’t come up with what I believe is a solution to the “gnomes” puzzle. In my solution, regardless of the number of gnomes (N), N-1 gnomes are guaranteed to survive the King’s challenge, regardless of the sequence of hats that the King chooses. Since each gnome can see all the hats in front of him and hear all the answers in back of him, here’s what he does. If the number of black hats in front of him plus the number of times a gnome in back of him said “black” is even, then he says “white”; otherwise he says “black.” In other words, the rearmost gnome reports the parity of the hats in front of him, and each subsequent gnome compares the parity report from behind him to the parity he sees in front of him - a sneaky way to both use the information and pass it forward. Here’s an example: The sequence of hats (back to front) is WBWBBBWBWW W: This gnome sees 5 black hats so he says “Black” (Incorrect) B: This gnome sees 4 black hats and heard “Black” once, so he says “Black” (Right) W: This gnome sees 4 black hats and heard “Black” twice, so he says “White” (Right) B: This gnome sees 3 black hats and heard “Black” twice, so he says “Black” (Right) B: This gnome sees 2 black hats and heard “Black” thrice, so he says “Black” (Right) B: This gnome sees 1 black hat and heard “Black” four times, so he says “Black” (Right) W: This gnome sees 1 black hat and heard “Black” 5 times, so he says “White” (Right) B: This gnome sees no black hats and heard “Black” 5 times, so he says “Black” (Right) W: This gnome sees no black hats and heard “Black” 6 times, so he says “White” (Right) W: This gnome sees no black hats and heard “Black” 6 times, so he says “White” (Right) To prove that N-1 gnomes are safe, consider just the front N-1 hats. The rearmost gnome reports the parity of the number of black hats. The next gnome compares the parity of the N-2 hat sequence in front of him with the parity the last gnome reported. If the parities are the same, he says “White”, because he knows that that’s the only way the parities could be the same and if the parities are different he says “Black” - in both cases, he both saves his life, and provides the next gnome forward with an update of the parity to use for the N- 3 case, and so on.
ShouldBeWorking Wrote: ------------------------------------------------------- > Aspiring Analyst Wrote: > > Hmm. I’m not sure I agree with/understand this > > explanation, but I suppose I agree with you > about > > the 9. I mean, basically the gnomes could > arrange > > it so that each gnome would just say the color > of > > the hat of the gnome in front of him. So > everyone > > but the 10th (the last one in the row, the > first > > to pick) will be guaranteed to live, and the > 10th > > just has to hope that his hat is the same color > as > > the one of the 9th gnome. > > what if you’re #8 and #9 just said black. but the > gnome in front of you has a white hat on. do you > save yourself or do you stick with the strategy? Yeah you’re right. I’m an idiot. Not sure how I didn’t think that one through.