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#1 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-14 08:29:13

ok in the meantime I will read up on recurrence relation

#2 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-14 08:23:33

Thanks Bobby can you teach me how you did this?

#3 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-12 16:26:05

Ok then the going broke option it is.  I have heard of Markov chains and monte carlo but I honestly have no idea how to input the data into them for this problem.

#4 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-12 16:10:54

Ok so if you have a starting bankroll of $5000 how long would it take to turn that intial $5000 into 1 million dollars AND what are the chances you end up going bankrupt if you dont reach the goal.  OR you can say that if you go bankrupt you are allowed to replinish the starting $5000 again.

#5 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-12 16:01:48

but isn't 232 losses virtually impossible, it is worse odds than a coin landing heads 232 times in a row.

#6 Re: Help Me ! » Calculating Rate of Return on Investment » 2013-02-12 15:50:52

You would keep adjusting your bankroll after each result so there would be no way to go broke.

#7 Help Me ! » Calculating Rate of Return on Investment » 2013-02-12 09:57:54

nflguy
Replies: 14

Say you went to the race track every day and bet on 3 horse races.  You are very good at what you do and are able to pick the correct horse 55% of the time.  The amount you wager on each race is 5% of your current bankroll which you calculate after each race.  Each time you win a race by picking the correct horse you add 5% to your bankroll.  Each time you are incorrect you lose 5.5% of your bankroll. 

The question is if you have a starting bankroll of $5000 how long would it take to turn that intial $5000 into 1 million dollars and how do I figure that out.

Second question is do the order of wins and lossess matter.



nflguy

#8 Re: Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 10:02:53

No programmer but I know HTML and dabble in sql server and I catch on quick to things especially topics that intrigue me.  I am the type of person that will use the excel functions for efficiency but I want to be able to know how to do it just for the knowledge.  Hell I was playing around taking quizzes last night on your site just for the fun on it.

I was always good at math in school but I dropped out before my junior year to start working so I am pretty sure I didn't learn this.  I kick myself now because the things I am interested in now math, science, history are all things I didn't pay much attention in school.  This may sound silly to some but I actually look forward to my kids bringing home school work asking for help because I want to relearn everything.  Anyway I really appreciate the help and the thorough explanation.

BTW I did find the formula on excel for those future readers that want to check their work in excel
=BINOMDIST(2,4,0.55, FALSE)

2 is successes
4 is trials
.55 is probability
true or false is for if probability is cumulative.

#14 Re: Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 08:50:55

I dont know what cdot is and how to do the 4 over the n.  Its been about 20 years since I learned this stuff and my memory just isn't what it used to be. sad

#15 Re: Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 08:42:57

bobbym wrote:

Where n is the number of heads.

Is this something I can do on a piece of paper by hand or is there a page on the website that explains it?

#16 Re: Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 08:38:04

Ah ok so this is a binomial problem, sadly I am not that familiar with how they work.  Ill have to go back and read up on the website to try and understand them a little more.  Can you do binomial formulas in excel?

#17 Re: Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 08:30:16

Yes I know that Bobby, I am asking how did you figure that out?  What is the formula to do so?

#18 Help Me ! » Probability of Independent Events With 55% Magical Coin » 2013-01-31 08:10:07

nflguy
Replies: 22

Lets say I have a magical coin that lands on heads 55% of the time and tails the other 45% of the time.  How could I figure out how often out of 4 flips it will land on heads 0,1,2,3,4 times?

I have figured out that
4 heads is 9.15% (.55 * .55 * .55 * .55)
0 heads is 4.10% (.45 * .45 * .45 * .45)

I know that the answer is for 3 heads is 29.95%, 1 heads is 20.05% and 2 heads is 36.75%.

The problem is I can't figure out the formula for those.  I was able to get the 3 heads using (0.55*0.55*0.55*0.45)*4 and the 1 heads by using (0.55*0.45*0.45*0.45)*4 but I dont even know if that is the right way to do it, and what the reason is that I have to use * 4 for those but the first two.  I still can't figure out the 2 heads formula I just subtracted the other values to get the number.

I would like to be able to do this using other values and numbers of flips so the explanation and formula to do this one would greatly help me out.

Tom

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