Added: 2 years ago
From: patrickJMT
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  • Thank you. This helped me understand expected value the day before my final.

  • have you published a book yet? I wanna buy your book and where did you get your studying materials? I'm currently studying to be an actuary, my studying materials such so much that make very little sense, can you help? thanks

  • If you play 100 times, you'll get bored.

  • Can you take my final?

  • @yuyupb sure, but i would just draw pictures and not actually answer anything

  • great job btw it really helped

  • . . . . it takes an art to teach math. . . . .Sir you have master this art.

  • @Srjuanando thanks : )

  • very good.

    thank you

  • Awesome. Thanks so much! This seriously helped with studying for my test.

  • thank you so much for your help on this! This makes so much more sense to me now!

  • i still don't understand this...

  • i swear if i hadnt seen this video i would of failed thanks i like how you dont make it sound confusing this vid should have a million views

  • Wow thank you so much!

  • wow ur better as a techer than mine i like how you make it easy to understand

  • I'm looking for creative ways to express the expectancy-value theory of motivation for a graduate class in adult learning. I just might use this! Math is not at all what I initially had in mind, but I love this and think I can spin it to work for my project. Thanks!

  • Could you possibly help me with a stats question???

    Mary has a free token to play a game. The probability that Mary will win the game is 0.05, so the probability that she will not win is 0.95. If Mary wins, she will be given $100, while if she loses, she must pay $5. Let X = the amount of money Mary wins (or loses).

    What is the expected value??

  • I think that X= -1, P(X)= 1 is not a valid variable, because I'll have -$1 if the outcome is 0, as I'll win $1 if the outcome is 2. Two different descriptions cannot stand for the variable X, which is NOT (as stated on the experiment) how much money will I win, but simply what is the outcome that falls on the spinner. Otherwise, we would have to change all the other X variables. So, the expected value would be 15/8 = 1.875, instead of 7/8.

  • @Agilulfa Actually, to make the piece of information "It only costs $1 to play" relevant, we would have to change all the variables, to make X stand for the amount of money one would win, but again, (-1, 1) would not be valid. Instead, the values would be: X= {-1, 0, 1, 9}, and P(X)= {1/2, 1/8, 1/4, 1/8}, and the expected value of X would be = (-1)(1/2)+(0)(1/8)+(1)(1/4)+(9­)(1/8) = 7/8, which is the same answer given, but justified enough, and for how much one would win, not for...

  • @Agilulfa ...which would be the outcome on the spinner.

    Please, let me know if I'm wrong and why, because that (-1, 1) makes it confusing.

  • you are a sweetheart....thanks for sharing your abilities 

  • One step closer to not failing my Alg2 class. Thank you very much :o

  • I don't know you... but I love you.

  • Forgive you for your artistry? DUDE you are forgiven. You're a lifesaver! Thanks!

  • Thanks

    Great Video (Y) !

  • wow, from just watching the first couple of minutes of this, i understood what to do. this whole week in class i have been confused out of my mind. THANK YOU

  • thank you very much Mr. Patrick

    your lessons are much much better than my teacher's lessons !

    the way you explain the details in a very simple way makes it easy to understand

    thanks again

    your student from saudi arabia :)

  • Great video. Thanks a lot.

  • this was very good thank you alot i am majoring in economics im in my first year and statistics has me lost without words but u did a great job thank you alot

  • thank you

  • This is AP CALC?!?!?! I'm learning this in Algebra 1!!! (and i'm starting to understand a bit)

  • @Stirfry0 no, this is not ap calc

  • i dont understand. If i bet $1 a game over 100 games thats $100 it cost to play, and if i only get 87.50 back????im down $12.50

  • @The100mis you miss the point: you win $.875 on average, so after 100 games, you would be up about $87.50.

    and of course, it IS possible to be down money (try going to a casino)

  • @patrickJMT but you still would have lost $100 to gain back that $87.50. why on earth would I want to play this knowing in the long run I'd end up loosing $0.125 each game

  • @patrickJMT I see what The100mis is saying, it really seems like you would be losing money every round. spend $1 to win .875 each round is losing .125. Can you explain this?

  • @yoshiyambao Taking into account my other commentary, I think there's confusion over what X stands for. If it standed for what one would WIN, not HAVE, and the expected value of X = $0.875, then, after 100 games, one would win $87.50, and one would have $187.50. That could have made it clearer for The100mis...

  • @patrickJMT Taking into account my other commentary (9 months later than these ones), I think there's confusion over what X stands for. If it standed for what one would WIN, not HAVE, and the expected value of X = $0.875, then, after 100 games, one would win $87.50, and one would have $187.50. That could have made it clearer for The100mis, but I guess she's not interested anymore...

  • @patrickJMT i believe what ur saying is.. gambling is a loosing game..unless u got lucky..but this game...a "low risk game" ?

  • @patrickJMT so you were saying, if I play 100 times, after invested $100, I will have $87.50 in my pocket?

  • @laucherhan I think the 1 dollar you spend in each game is already factored in calculating the E(X)

  • Thank you very much!!! I really appreciate this video!! It's helping me out with a different kind of example. Thanks again!

  • AP CALC exam? statistics? I'm only a freshman and learned that. . 0-o

  • Why us it 1/4?? There are 5 outcomes, shouldn't it be 1/5????

  • @blackstars56 I assume you mean the probability with the amount you win, correct? He's going by the area of a unit circle. In this case, the probability of winning $2 is around 1/4, or 25%. If you cut a circle up in 4 equal parts you'll get it. Same can be said about earning $0 is another 1/4 but there's two parts so that can be 2/4 or 1/2.

    Even so there's only 4 different options of money you can win. $0, 1, 2, and 10.

  • @KiddyBrucie15 yeah i realised each part of the circle wasn't equal, thanks anyway

  • You sorted it for me - thank you very much for some amazing videos, you really are amazing with these.

  • I'm lost in Statistics. This helped a lot.

  • Patrick, thank you so very much for ALL the videos that you have posted. They have been very informative, and I feel confident that I will do great on my Advanced Stats exam thanks to you. You rock! :)

  • Hi Patrick,

    I just want to say thank you very much for ALL the videos you post. They are very informative especially when you can't really understand where and how to use the different formulas. You have been very helpful, and I feel confident that I will do great on my Advanced Stats midterm thanks to you. Patrick, you are amazing! :) Thx!!!

  • Thank you so much!! :)

  • Would it not make more sense to subtract one from each of the positive outcomes? While you will definatly lose $1, if you land on $2, you gain $2, so overall you win $1. So there would be a 50% chance you lose $1 overall, 12.5% chance you break even, 25% you win $1 etc. Also, I was taught the probilities should add up to 1.

  • I think you need to redefine your X random variable in the example, as the sum of the probabilities is higher than 1. Suggestion: X = winning, Y=paying. Profit=E(X)-E(Y)=0.875

  • neat.

  • but since 0 takes up 2/4 that means all the other numbers take up 2/4 and isn' that 50/50? I get what you mean but just a little question that i randomly thought of.

  • really good eg

  • This is easy. Why does this need to be studied. People should know this by heart. 

  • @LycanthrA lol, what a silly comment to make

  • @LycanthrA hmm.. i somehow agree. i don't really use it in my daily living, unless i end up being a gambler? =) however, if it's being taught, i guess it's somehow important?

  • @ThisIsMe812 i bet almost every decision you make in life is really some variation of expected value. for example i mean, why not drop out of school? because the probability of getting a decent job goes up with an education. does one have to go to school to get a good job? of course not...

  • @ThisIsMe812 and besides, how much of what you learn in school do you use in 'daily living' ? having a job usually means having a skill and having it mastered better than others. if math is not gonna be your skill, that is fine, but for some, this is a skill that makes money! me for example... i make my living understanding math! so to me, it is extremely useful : )

  • @patrickJMT oh. i'm really sorry. i didn't mean an offense.

    damn right. it's just that, well, i guess, hmm, i just dont want to confuse myself with those things. i can always go on with my life without calculating the expected value. weigh the pros and cons.like that, without computation.

  • @ThisIsMe812 i was not offended in the slightest. just pointing out that 99% of what you learn in school ends up being useless. people just seem to fixate on math though for some reason (i guess cause they have to think).

  • @patrickJMT with that, i agree. well, many students hate numbers. =) i've done reading about stat, well', largely because i was bothered by this. and i figured that stat really do us good. take convicting a felon, for example, just by finding probabilities!

  • If a had a teacher like him in college , I would be now a Nobel price winner in maths.

    Bravo - this is honnestly the way for teaching childs in a pleasant way. Bravo - Patricos Koronos

  • thanks for ur video..but main problem in practical life is how can we find expected output and how can we assign weight? because Random number are not capable to bring real expected return. Most tough thing is finding expected outcome and giving them probability weight........................­.

    please tell us for that

  • I dont understand why I am learning this in my college math class when the class I am taking is designed towards elem. students. Do elem kids need to know this?

  • Patrick, you say we would play the game but i feel otherwise. If for 100 games we can win approximately a total of $87.5 but to play a 100 game's we'll have to invest $100. Do you feel its worth it? Please explain Thanks.

  • I am in tutoring for the first time in my life because my college xfer from JC to UC depends on this stats class and my gpa (which is fine, except for math). I am really determined to do well in this class, and this video is great. I learned today in psych that if you go home and review the material the same day that you learned it in class, it will help you to retain it- so I can sit here and eat dinner while learning and solidifying my understanding. You're passing me through college!

  • @BlikeNave there have also been numerous studies done that show if you study/read something right before you go to sleep, it much more readily gets processed into your memory.

    i used to always look at important stuff for about 10-15 minutes before sleep... you will find you are thinking about it while you lay there, which can be good and bad!

  • @patrickJMT Good to know. I'll watch ur vids right before I pass out then X] Thx!

  • how about one where we are looking for the expected profit. example insurance policy is 600 amount it cost the company $1200 amount for each policy holder hospitalized. furthermore the have estimated that 85% of policy holders will not be hospitalized, 10% will be hospitalized once a year and no one will be hospitalized more than twice.

  • Ur a great teacher everytime I don't get something I go to you! Thank you.

  • thanks

  • sir u are a gift from God.

  • thanks u really helped me with my math.

  • my teacher can`t teach.. I just realised why it makes sense. this video is so helpful...thx

  • Nice! You are a life savior!

  • u r the man..

  • very nice explanation

  • Thank you so much, this really helped!

  • sooo helpful!

  • Why cant all teachers break it down like that? Im taking stats in college and my professor is horrible. He is all over the place and expects us to know too much already. Thanks a lot man. This really helps. 5/5

  • I just realised why it makes sense... you have to keep on playing. Only rich people can afford to win at the casino...cos thay keep on playing!

  • That spinner is biased toward low dollar values ;P

  • good explanation. thank you.

  • I took the AB test and I thought I did good when I took it but now I'm realizing I made so many dumb mistakes. :(

    Great vid!

  • hi I just took my test AP TEST lol i feel good about it how about you guys?

  • So I think you so do a follow up where you make the bell curve and calculate the Standard deviation. Use a problem simialar to this. or if you want this on since you already have the mean. I wonder would it follow the empirical rule?

  • what math is this? calculus?

  • It's probability theory.

  • lol yeah duh :3

    it showed up on my IB math SL practice exam. very helpful!

  • wish me good luck on my AP CALC exam..

  • I am with you, good luck, i also take it tomorrow!

  • My school did something and I take it on the 21st

  • goooooooooooooood luck! : )

  • Thanks ..and thanks for everything..u are da best !!

  • ok about the you aced mine thing your really smart lol are you smart on other subjects though?

  • i took the ap calc bc exam today

    i thought it was so frikin hard D:

  • indeed !! it was tough

  • exactly, i couldnt get #6 on the non-calc FRQ no matter what, and nobody in my class got it

    it was pretty darn hard!!!

  • SAME! all the people in bc calc class said the same =\ hopefully the curve will be very generous this year

  • hmm, when are you suppose to learn about this?

  • not everyone will see this.... it is taught in just about any statistics class, and sometimes in a probability/discrete math class.

  • any clue on how to do significance tests or will that be too long winded to explain in a video??

  • to be honest, it has been a long time since i taught stats. i plan on making some vids over the summer (too late i know) about stats though. i need to refresh myself first though.

  • nice video

  • thanks!

  • PAT please make tutorial on simplex method of linear programming...

  • yes! please do.

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