Statistics 101: What is Expected Value?
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- Опубликовано: 5 июл 2024
- Statistics 101: Expected Value.
In this video, we discuss the basics of expected value. If you have ever calculated a weighted average you can easily calculate the expected value. Several practical and concrete examples are provided. Enjoy!
My playlist table of contents, Video Companion Guide PDF documents, and file downloads can be found on my website: www.bcfoltz.com
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i love you brandsom!!!!! i got 49/50 marks in this topic in by school!
hi! how did u understand projected profits terrific taco's?
EXTREMELY HELPFUL!!!!! Excellent clarity and I love the way you have your videos organized. Extremely thorough!!!! I'm not as stressed now for my midterm at all!!!! God bless you!!!!!!
Your videos are extremely helpful, Brandon! It feels great to be able to understand the material.
Thanks for the lesson. I like that you take your time. You always give multiple examples.
Excellent videos, Brandon - thank you for taking the time to help us out! Just a note: I get E(x) = 3.921 for the class satisfaction survey example.
I want to thank you for taking the time in explaining. I find your videos most helpful. You are a great teacher.
Wow. You do a terrific job explaining what can often be diificult topics. I am blown away by your thoughtful preparation
Thank you so much; your videos have been so helpful to me during my intense 6 wk statistics course!
Hi Brandon great explanation. Please note for 1.5M value the probability is given 0.10 while calculating the expected value you are using a probability of 0.15. Even though this doesn't affect the concept in any level I just wanted to point out that typo. If you can change it that would be better to avoid any confusion.
sometimes youtube lectures are far better than college lectures.. thank you for this video!!
Perfectly explained and very helpful. Thank you for taking the time to make this video :)
Thanks Brandon, I am taking a Stats 520 class and this video made it much clearer with simple examples, although its hard to understand the practical use of population mean at this point, but i am sure that in subsequent topics like Variance, SD, it would come handy.
Wow, you really helped me with this video. Expected value looked so scary with the greek characters but it turned out to be a surprisingly intuitive concept. Thanks!
How can you be so good at teaching and educating??!!
Best explanation I have ever seen......Thank you Brandon
always help full in understanding difficult topics
Thank you for your instructional videos. They are extremely helpful.
Excellent videos Brandon! Of all your videos that I have watched, this is the first one I have come across rounding (or some other type of calculation) errors I have never seen in your videos before.
For the class satisfaction survey, I got E(x) = 3.921 to 3.926 depending on my rounding, and for the Terrific Taco profit Taco for P(1.5) you have 0.10 written in the second column, but calculated using 0.15 in the third.
Hi Brandon. Your videos are amazing. Thank you so much for this amazing content.
beautiful. simple. effective. good work
I love your videos they have helped me so much! I am going to school online I am self teaching so long story short I have hit a wall in my statistics 1 class somewhere I missed some concepts and am now struggling to finish an assignment. So long story short I found your video's and have watched several I thought I understood how to get the probability but I must have missed something because I thought you would have taken the outcomes added them and divided by the possible outcomes
Hi Brandon, Thanks for all the videos. I am really new to stats and your videos are helping a lot. Simple query, in the third example how did you calculate the probability or the values were provided as the introductory example.
Once again thanks and God Bless you... :)
Thank you for this video. It helped me so very much with Probability 100
I'm very much enjoying your videos; they've been quite helpful. For this video, however, may I suggest you elaborate on the differences between finding the expected value of a random variable (aka, its mean) and the conventional approach to finding the mean, i.e., sum of all values/total number of values.
And your videos are really great. Thank you! Thank you very very much
Awesome presentation, many thanks
This was mad easy. Thanks so much for this :)
much respect to your work!!
REALLY GOOD EXAMPLE . thank you !
Good video, great explenation. You have some rounding errors though. The actual overall satisfaction level in the class is not 3.7 but 3.926
Actually 3.921 according to mine
Excellent video Brandon. Any chance of finding out where the probability column comes from in the Taco example?
You are an awesome teacher
finally, now I know what the expected value is and I can solve my exercise
With the discussion of talking about Terrific Taco's projected profits, when you put (x) outcomes and did it ever .5, does this include the cents or decimals that are included in making money? It is rare someone makes a certain set dollar amount. Usually it includes cents. So if it does, how do you fit it in between each category?
Hi Brandon, great video! I just wanted to mention that you might have mistakenly put 1.5*0,15 at 18.41 mins. It should be 1.5*0.10 right? CHeers
Hi Brandon. In the example of "Projected Profits" I get a different expected value. Can you confirm if you made a typo in the 5th row? Cheers!
Excellent.. Thank you.
You're great man 👍
Thank you! This was SOOOOO Helpful. =)
Hey, for the last project of the video, how did you find the probability of x
This was soooo helpful :) thanks! And just a minor error- at 18:51 u accidentally mutliplied 0.15 by 0.15 instead of 0.1 (in the P (x) column)
Thanks for the video, how about the E(g(x)) kind of problem ?
Can someone tell me how you got the P(x) in the last problem or was this given?
How did you get the p(x) results in the taco problem?
Buddy you saved my life
You have wrong math in the last example though: You said that for 1.5, the probability was .10 but then in the math, you used .15 instead of .10
Very nice explanations. Thank you very much❤
Glad it was helpful!
i wanna to get the intuition and the sense behind this number "the mean or expected value
what this value "3.7" told you about the quality"how much satisfied" of this course ?
This was very well done, thanks!
Great video
Sir I am biology student, so have no speciality in statistics. i have final multiple linear regressiion model, i need to calucalte obsereved and expected value from the regression coefficients, how will i do that? i am waiting for your response
Thank you!
Thank you! It helped. ;)
Can you please tell me how did you get the P(x) values.
P(X) is the notation for the probability of an event (x, which in our case is called random variable) to happen. Either you are given this value or you calculate it.
Brandon
Likert scales are ordinal data, so how are you calculating the average? Could you please clarify.
Thank you
Andrew
That’s what I thought also
The numbers 1,2,3,4,5 are for labeling purposes only. It only represents values (frequencies). It is not a scale data. Can someone explain to me why the speaker perform multiplication {xP(x)} using this ordinal data (1,2,3,4,5)
Thank you
Helpful. Also, some numbers do not add up for me. In the student survey problem, the answer I got was mean = 3.921. In the Terrific Taco's problem, the answer I got for x(P)x for 1.5x is 1.5*0.10=0.15
I can't understand the scale of overall satisfaction can we calculate it any other way without using expected value formula..
i didn't get why you are multiply with 1,2,3,4 and 5? what is the logic? is it for weighted average? then what is the purpose? can you clarify it?
So is this basically the same as weighted average
Kindly explain how did we calculate @18.20 P(x) Probability values?
How did you get p(x) in Terrific Taco?? i think frequency count is missing
How did you get the count to get P(x) of profits?
very helpful
Can you refer me the 1st playlist link
When I add the results of X x P(X), I keep getting 3.92, not 3.70....?
3.92 is correct
Hello,I have a question. How did Brandon arrive at the count as 5,10,11,44 and 38.Or it was an assumption
There is a slight error in the Terrific Taco Company example: for x = 1.5, P(x) = 0.1, not 0.15.
what is the difference between expected value and the arithmetic mean???
arithmetic mean is the sum of each value divided by the total number of values, the expected value is the sum of the value times its probability. Also you cant do arithmetic mean in a continuous variable, you have to do an integral using expected value
Very useful and intuitive learning, but one thing is bothering me. In the Class Satisfaction section the evaluations are from 1 (very dissatisfied) to 5 (very satisfied). What is the reason for this order? Is it some kind random, or something else? Let's say I want to evaluate by my own order. Say "very dissatisfied" be 5 and the number one let be "very satisfied" (they are the top :)). In this case the expected value is totally different! What is the reason for this? Could you please explain why, by just another categorization, the expected value moves to another levels ... or there is something I miss?
it's just personal preference. besides, it's already common occurences in game or movie industries etc. to score from 1 (bad game/movie/etc) to 5 (good movie/game/etc). if you like it, you could also reverse the score, where :
5 = very satisfied
...
1 = very dissatisfied
of course the value would differ if you put it as above, because now the mean/expected value shifted to the opposite side too.
So, for simplification purpose, imagine if expected value e(x) of class satisfaction in the video is 4 (satisfied). if you reverse the score to (1) very satisfied-- (5) very dissatisfied, now the e(x) is located at 2, but it's still on (satisfied).
I think you should next time involve bigger numbers and decimals like something along the lines of Expected value of winning the New York Lottery
Thankyou for clear explanation, but i think there is a mistake with graph pronunciation, you are saying graph as right skewed instead of left skewed.
but i just dont understand one thing, why multiplication on dice sides as if they are value, coin is different because it takes on 2 probabilities head or tail, yes and no
good video but why did u change the .10 to.15 in the last column doesn't that mean the answer is wrong because every other answer kept the same variable at end besides what is represented in the column for 2 million
wow.
i meant the 1.5 column
I want these slides, can you send me plx?
The expected value for the class satisfaction problem should add up to 3.921
I think the expected value for class satisfaction should be 3.921. Or I've entered an alternate universe
minor error 19:06 it should 1.5 * .10 instead it's 1.5 * .15 at fifth row.
.046+.186+.306+1.628+1.755 = 3.921....
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Other's have pointed out it may have been due to rounding, or I made an error or typo. I will take a look. Thanks!
An 87 is an A...
Please be more careful when you write formulas. After the Summation sign, the rest of the formula should be inside brackets. I was confused at first because the way it's written doesn't make any sense as you can't add the individual probabilities that way.
handballvid Hello! Thanks for your comment. If you are referring to the formula around 6:11 I just double-checked and it is correct as written in the video (Statistics for Business and Economics, 12e, p. 225). We multiply each value of the random variable by its corresponding probability and then sum the products. Different texts sometimes write the same formulas a bit differently and this may just be one of those cases.
handballvid you use brackets when dealing with summations or substractions (variance formula is an example), for product or divisions, you do not have to use brackets in summation operators...
+Brandon Foltz I have 1 question and that is when we calculate mean , we do add the 'n' values available to us and divide it by 'n' . Why in this case we didn't do that? That's cause me lot of confusion