How to Calculate Conditional Probability
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- čas přidán 22. 08. 2024
- Tutorial on how to calculate conditional probability (Bayes Theorem) for two events P(A), P(B), P(B|A) with two examples using
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Created by David Longstreet, Professor of the Universe, MyBookSucks
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11 years old and is still the clearest video i've come across so far. The visuals helped so much. I appreciate you!!
Please continue to post these very clear and concise explanations. These videos are by far some of the most clearest explanations of statistics. Probability of finding a video as this: one in a million.
youtube - helping bachelors since 2007
Thank you for the feedback!
Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
The pace is always hard for me because the CZcams audience is so diverse. My target audience are those students that are struggling with statistics and I have learned that for a struggling student the pace can never be too slow.
This was an absolutely incredible video. Far and very far better than a stats course I am doing.
Thank You! This is the best explanation of conditional probability I have come across. The Venn diagram and the verbiage "they interset 2 out of 6 times" really drove home the meaning of P(A∩B)
Thank you so much for your positive feedback! Much appreciated.
Make sure you like MyBookSucks on Facebook (see link in video description). This will help other students find the educational video.
Good luck in your classes, too!
I just became the 1000th person to like this video because you, sir, deserve it. Thanks!
Thank you! I'm taking stats for the first time this year as a senior in high school and most of it comes pretty easy but this is something I was never able to wrap my mind around! This was very helpful for me and I feel so relieved!
Wonderful to hear the videos are helpful for you and I do appreciate the feedback.
Make sure you like MyBookSucks on FaceBook (see video description for link). This will help other students find the educational videos.
You’ve been the first person to get me to understand this. Thank you!!!
Super helpful and working step by step is super helpful. Thank you so much for this video!
I was getting so frustrated because I couldn't figure this out but your video was a LIFE SAVER. Thank you so much!
THANK YOU! After numerous searches I finally came across your account! This is the one that made it click!
This was the clearest explanation of this concept I've seen anywhere. Thank you.
So easy to understand. I didn't feel it was to slow at all, bc I need time to process what you say before you start on something else. great job!
spent whole night tryna learn conditional probability this video taught it the best
Indeed! This is a visual learner's paradise. Very well done! I'm so glad I found this site!
Thank you so much, My teacher taught us this today, and he lost me in the beginning, you made it easier to understand what P(B) and P(A) is. I watched the video twice and I am starting to understand it more and more. Thank you.
Appreciate the great feedback. Make sure you tell your friends and classmates about MyBookSucks and like us on facebook to (see the link in the description of the video).
Thanks again!
one of best intuitive animated video make probability learning more fun..thak you sir.
The pace and length for me is always a struggle because the CZcams audience is so diverse. Thanks for you input.
Great example! The first time I have seen a complicated subject explained in very understandable terms.
You are the best. Man, love your videos, keep it up. You deserve a like and a subscriber. Thanks.
I have final exam in the morning, needed refresher, and love the slow pace !
Thank-you so much! I've been in the hospital for a while and I have a lot of school work to do. Most of it is easy but conditionals are super difficult. I've never seen anyone who made math this understandable!
Your teaching process makes me easy to understand.Thank you sir.
Even better than my teacher.
Precise, to the point, easy to understanding.
How I wish you were my Math teacher:(
Great, I've a Stats exam in a few weeks and you're making my life a lot easier with these videos!
You are very welcome. I appreciate questions because it helps me understand what students are struggling with and then I can create right videos.
Thank you! My teacher couldn't tutor me today & I have my finals tomorrow. Thankfully I saw this video!
You are very welcome.
Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
i got it finally.......a great help for my CAT preps...thnx prof...
I think you are referring to when I change the problem starting at about 5:34 in the video. In the second half of the video, I change the problem from P(B) being an odd number to P(B) being equal to 1.
Make sense? If not let me know and try to expand on your question a bit.
my best teacher ever💯👍🏻 my QUANS teacher sucks!
Thanks for clearing my basics. I am studying after 16 years and preparing for CFA.
Thank you for you feedback. Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
really helps seeing it drawn out and explained step by step like this, really helps thank you!
You sound like the guy from OwnagePranks... nice video tho :)
Alisha Daswani I have heard that from a couple of people now. Interesting. Hopefully you will like, share, subscribe, If you get a chance could you please like our FB page. www.FaceBook.Com/PartyMoreStudyLess
It will help others find the videos.
Who knows ?
Ownage maths prank ?
Haha
You are very welcome and I do appreciate the feedback. Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
You are welcome! Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
Many Thanks! Make sure you help me spread the word about the free videos. One thing that helps is if you like MyBookSucks on Facebook (see link in the video description).
Using the visualization of the dice was very helpful. That alone allowed it to click for me. Thanks!
And thx for actually taking the time to at least go through some of these, and thx for the econ videos they really were super valuable for International Econ class and understanding the trade models.
Better than my math teacher... Thank you!
Thanks this helped! Your wording of the formula is what made the difference for me! :-)
That is great! Make sure you like MyBookSucks on FaceBook (see link in video description). This will help me spread the word about the educational videos.
THANKS! Im seriously studying this before my exam in 2 hours!! LOL
Luis Mendez So.. you were "partying more studying less" If you get a chance could you please like our FB page. www.FaceBook.Com/PartyMoreStudyLess It will help others find the videos.
Good luck on your exam, you can do it!
statisticsfun this video is very useful! thank you very much.
Luis Mendez for me 15 minutes...
me
Great suggestion and it is my plan to have a series of videos on Bayes Theorem. I hope to have one done within the next week or so.
Will do. I'm studying to become a math teacher and find these videos to be of tremendous help ;)
U r genius man.. as always thx alot.. Statistis is really fun because of u
Great to hear!
Make sure you like MyBookSucks on FaceBook (see link in video description). This will help me spread the word about the educational videos.
you explained this really well and i appreciate that you went slowly, thanks so much!
Well thank you very much and I appreciate the feedback. Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
+statisticsfun Nice presentation, especially the visual aids :>
Just a minor nitpick: it would be nice if you included the 4 and 6 dice outside the Venn diagram, for completeness of the sample space. Then it would be easier to see where the 6 in the denominators comes from. It is a bit confusing when there's a 6 in the denominator, but one can see only 4 possible dices on the diagram.
Also it would be nice to show how the "|A" shrinks the sample space to just the P(A) circle on the diagram. I see in the comments that there were some people who were confused by that. Showing that the "|A" part makes the sample space to choose from smaller - or throwing the impossible cases out the window in that matter - should make things easier to understand.
That is great to hear. I was going to name my company/website/FB page -- MyProfessorSucks but went with MyBookSucks instead :). Make sure you like MyBookSucks on FaceBook (see link in video description). This will help other students with horrible professors find the videos.
Thanks!
This has made it much clearer for me, thank you!
Thanks and it is my plan to build examples to help people do better on the GMAT / SAT / ACT, etc.. Good luck on your GMAT too.
Thank you and good luck in your classes. Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
Hi! Your graphics are fantastic, your examples are fantastic, and your pace is extraordinary! I found the video quite confusing, though, because the phrasing/wording didn't correspond to what you were trying to say. If you fixed it, it would just make your work AMAZING.
For example, instead of saying "What is the probability of rolling a dice and its value is less than 4?", it would be clearer to ask "What is the probability of rolling a die (or dice) and getting a value less than 4?" That way, you're asking about which number is shown on the die after it's rolled, not about some kind of value for the die itself, as though the cube has some kind of intrinsic value with an assumed unit ;) Also, instead of saying "knowing that the value is an odd number is event A", it would be clearer to say something like "Event A is rolling the die and getting an odd number", and separately explaining that the vertical bar for "given" means that we know that A is true. There are other things, like saying "and" before "knowing" instead of just going straight to "knowing"... They might seem like small improvements, but I really think they would make your presentation shine!
Asher Vijay Yampolsky Asher thanks for the feedback. I am always looking for ways to improve my videos. It is a struggle for because I narrate on the fly instead of working from a script.
Ah, I understand!
+statisticsfun How about recording your "on the fly" approach first, and then making a script out of the best parts of it, correcting any mistakes and improving it in between, and then recording it again with a script at hand? :)
Why would a die have an intrinsic value with an assumed unit? lol.
Love it. Thank you so much. Refreshing my old maths knowledge. You sir, are a legend!
You are very welcome.
While I can't be your teacher, I can post videos for you. And I do call myself the "professor of the universe" :)
Re-Brushing this for GMAT, very well done. Should give some thought on using actual example from standardized tests.
This was lovely... I thank you i have aa horribble professor aand this helped sooooo much!
This was very helpful, thank you!
Well, thank you! Make sure you like MyBookSucks on FaceBook (see link in video description). This will help others find the educational videos.
Thank you for simplifying probability for me 😊
You are welcome and good luck on your CFA!
Perfect explanation!
Great to hear and good luck on your test too! You can do it.
Many thanks for your feedback, much appreciated.
This was amazing!!! I was trying to figure out (the sum is at least 10, given that the sum is at least 9). I figured it out after watching this video!! Thx!
Yes, you can use a decision tree to help understand conditional probabilities.
Hi! Thank you. This was so helpful considering the fact that I have been finding stats so difficult.
Let me know when in the video you are questioning. This will help me answer your question.
Thank you so much for making conditional probability much clearer. I still have one question though. Could you show the same example, but with the P(A) and the P(B) being for much larger pools of data, where it would be impossible to draw the overlapping segment. I'm still having trouble visualizing that. Thank you
If I'm understanding your question correctly, it should be the exact same calculations, the only difference is that you wouldn't be able to illustrate your whole sample space in a Venn diagram. For example if you want to figure out how many face cards out of a hundred poker decks are of a particular suit, A would be the total number of face cards (1,600), B would be the number of cards of that suit (5,200). You're not going to be able to visualize that, but it's the same equation: 400 (number of face cards in each suit) /1600 (total number of face cards) =1/4
notoriouswhitemoth correction, 1,300 cards of any given suit
Thank you so much. I try to use 21st Century Tools perhaps that is the difference.
Make sure you like MyBookSucks on FaceBook (see link in video description). This will help me spread the word about the educational videos.
good teacher
+Tc Pham Thank you for your kind words. Hopefully you will get a chance to share and like the videos. This will help others find them.
Your animations are nice, your pace really good..... However.... there are some really important concepts you fail to explain, which leaves gaps in the reasoning.
1) How do you do this without the Venn-diagrams?
Answer: you can't. You have to know the intersection, or the whole exercise is doomed. When rolling dice it's easy to see, with thousands of items it's not so easy anymore. It's misleading to talk about P(B) because in the whole reasoning and calculations P(B) is not even used, it's irrelevant. P(A n B) is relevant, but it can't be calculated by a known P(A) and P(B). In this example the fact that P(A|B)=P(B|A) might also mislead students to think that this would always be the case, which it certainly isn't.
2) Why do you divide the outcome of the intersection by the 'given' propability?
Answer: a given probability is like a 'total set'. You know for sure it's 100% true already, there is no doubt, it's given. That's why it says 'knowing that', and not 'hoping that'. The 'total set' is always the denominator of the equation for probabilities: something happening out of everything that can happen.
In fact if you look at the Venn diagram of P(A) at 1:18 it is immediately clear that the chance is 2/3 without any calculations. The colored part has 2 items, the entire circle has 3 items. If we translate to the 'larger set' we can see the equation (2/6)/(3/6) which we can simplify by multiplying numerator and denominator both by 6.
But the larger set is irrelevant, since we take samples A and B from the same set (6 sided die).
The time you took in your video to explain the calculation of P(B) should have been used to explain why P(B) is irrelevant, and why P(A) is the total set for the equation!
Michiel van der Blonk My goal with all my videos is to help student understands the basic concepts, not to be a comprehensive end all 3 hour long video. Just trying to introduce the basics.
+Michiel van der Blonk Thank you for point 2) this was exactly what I was sitting here trying to figure out!
Michiel van der Blonk r
thank you very much for this video, the best explaination I have watched!
Good question. If you look at the video starting at about 4:30 you will see that I use P(A) and P(A) and the intersection is P(A∩ B) not P(B). Is this what you mean? If not let me know the time in the video that you are talking about.
that's totally amazing
You can only square the probability of two events occurring simultaneously if they are independent. These probabilities are not independent. This is called the "multiplication rule for independent events."
you are a great person.
If both events have a 3/6 chance of occurring you can square the events to get 9/36 which is the joint probability right?
Now, b/c this is a conditional you divide the joint prob by the conditional event which is 3/6.
So, 9/36-the joint prob-divided by the conditional (3/6) is 54/108 which in decimal form is .5 which I got for the answer using the formula. Without the formula 2/3 makes sense for the answer.
Hopefully that wasn't too confusing.
Whoa! I am not afraid to Statistics anymore! Thank you sir..
I probably misunderstood you. I get that only {1,3} are odd and less than four. But how did you get 2/3 for the answer using the formula? If P(B)=rolling a value < 4, which its probability is 3/6 or 1/2.
P( A)= knowing the roll is odd, which its probability is 3/6 or 1/2. Formula P(B given A)=P(A*B)/P(A). 1st multiply the two events for joint prob, (3/6)^2. I got 9/36 or 1/4. Then divide that by the new sample space which is A or 3/6 for .5 or 1/2 as the answer.
Wow! Thanks so much for clearing that up for me!!!!!! :) I appreciate your time and effort!!!!!
thanks alot sir, your video is very clear!
Prudencia Kigosi You are very welcome! Good luck in your classes.
Thank you, you made it much more clear.
very nice explanation
Do make sure you "like" MyBookSucks Fan page on Facebook. I have some fun items (like my freshman student ID) and other college humor.
that was so helpful ☺thanks
great example. thank you.
That was great and couldn't have come at a better time! Thanks!
Could you do something like this for Bayes Theorem please?
Thank you very much! so helpful!!!
amazing!
Great videos, they've helped me a lot. I'm very impressed by the illustrations and was thus wondering if you could share what program(s) you've used to make these videos?