Statistics 101: What is Expected Value?

Рет қаралды 141,262

Күн бұрын

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

Пікірлер: 96

@internationalremixes6440 6 жыл бұрын

i love you brandsom!!!!! i got 49/50 marks in this topic in by school!

@adilismagulov9974 5 жыл бұрын

hi! how did u understand projected profits terrific taco's?

@sheilaang1987 9 жыл бұрын

Your videos are extremely helpful, Brandon! It feels great to be able to understand the material.

@DjHandzsolo1973 10 жыл бұрын

Thanks for the lesson. I like that you take your time. You always give multiple examples.

@tbelle08 9 жыл бұрын

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!!!!!!

@jal492 9 жыл бұрын

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.

@efrosynimaher3454 9 жыл бұрын

I want to thank you for taking the time in explaining. I find your videos most helpful. You are a great teacher.

@virginiah2036 9 жыл бұрын

Thank you so much; your videos have been so helpful to me during my intense 6 wk statistics course!

@paulstuart3171 9 жыл бұрын

Wow. You do a terrific job explaining what can often be diificult topics. I am blown away by your thoughtful preparation

@sachinsivankutty2075 Жыл бұрын

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.

@petercourt 4 жыл бұрын

Perfectly explained and very helpful. Thank you for taking the time to make this video :)

@abhishekarya20 7 жыл бұрын

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.

@AlexReyesInHD 3 жыл бұрын

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!

@spoddar77 3 жыл бұрын

Hi Brandon. Your videos are amazing. Thank you so much for this amazing content.

@aaskyboi 5 жыл бұрын

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.

@farmad100 6 жыл бұрын

always help full in understanding difficult topics

@Surya42930 11 жыл бұрын

Best explanation I have ever seen......Thank you Brandon

@jiayiluo9260 5 жыл бұрын

How can you be so good at teaching and educating??!!

@Prismer6 9 жыл бұрын

Thank you for your instructional videos. They are extremely helpful.

@avsgriffy Жыл бұрын

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.

@schrodingerscat3912 6 жыл бұрын

beautiful. simple. effective. good work

@CDJohnson58 8 жыл бұрын

Thank you for this video. It helped me so very much with Probability 100

@pamelas5675 11 жыл бұрын

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

@anandreddy9585 4 жыл бұрын

This was mad easy. Thanks so much for this :)

@Maria-hx7ix 8 жыл бұрын

And your videos are really great. Thank you! Thank you very very much

@ahmedsurajuddin967 7 жыл бұрын

much respect to your work!!

@mohsenhs 7 жыл бұрын

Awesome presentation, many thanks

@jagadeshdevaraj2052 2 жыл бұрын

sometimes youtube lectures are far better than college lectures.. thank you for this video!!

@MrSubir87 7 жыл бұрын

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... :)

@lennydee707 8 жыл бұрын

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

@tetheredminds6019 2 жыл бұрын

Actually 3.921 according to mine

@rocketleague2136 4 жыл бұрын

REALLY GOOD EXAMPLE . thank you !

@haal4056 6 жыл бұрын

You are an awesome teacher

@theputalas 9 жыл бұрын

Thank you! This was SOOOOO Helpful. =)

@ioannismarkoulakis4978 6 жыл бұрын

finally, now I know what the expected value is and I can solve my exercise

@helen4805 2 жыл бұрын

Excellent video Brandon. Any chance of finding out where the probability column comes from in the Taco example?

@firstkaransingh Жыл бұрын

You're great man 👍

@prabhudaskamath1353 4 жыл бұрын

Excellent.. Thank you.

@ramireddyvarun26 4 жыл бұрын

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

@vivianbaez385 7 жыл бұрын

Thank you! It helped. ;)

@Wowhondor 8 жыл бұрын

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?

@vishnumurthy4432 7 жыл бұрын

Great video

@taramcgara1 10 жыл бұрын

Thank you!

@GuyingZan 10 жыл бұрын

Thanks for the video, how about the E(g(x)) kind of problem ?

@danielkeegan5484 8 жыл бұрын

Buddy you saved my life

@florentinosanchez3969 4 ай бұрын

Very nice explanations. Thank you very much❤

@BrandonFoltz 4 ай бұрын

Glad it was helpful!

@SacchinThomas 4 жыл бұрын

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

@n.h.6139 7 жыл бұрын

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!

@k.phoenixgarcia8703 3 жыл бұрын

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

@o0Sweetie0o 11 жыл бұрын

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)

@ManMattWhat 6 жыл бұрын

Hey, for the last project of the video, how did you find the probability of x

@murewa26 7 жыл бұрын

very helpful

@Noony202 8 жыл бұрын

Thank you

@derrickappelzoller8633 6 жыл бұрын

Can someone tell me how you got the P(x) in the last problem or was this given?

@toddmartinseyebrows 8 жыл бұрын

This was very well done, thanks!

@aliel-kassas478 7 жыл бұрын

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 ?

@thirstysoul9869 6 жыл бұрын

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

@manojinbox 8 жыл бұрын

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?

@trindamartinwolfe9554 5 жыл бұрын

How did you get the p(x) results in the taco problem?

@karthiknedunchezhiyan7935 6 жыл бұрын

I can't understand the scale of overall satisfaction can we calculate it any other way without using expected value formula..

@PrakashKumar-jd4um 3 жыл бұрын

Kindly explain how did we calculate @18.20 P(x) Probability values?

@efrosynimaher3454 9 жыл бұрын

Can you please tell me how did you get the P(x) values.

@badoiuecristian 4 жыл бұрын

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.

@kanyewest132 8 жыл бұрын

Brandon Likert scales are ordinal data, so how are you calculating the average? Could you please clarify. Thank you Andrew

@fgiegarra2177 3 жыл бұрын

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)

@aleksandarjankovski6542 11 ай бұрын

There is a slight error in the Terrific Taco Company example: for x = 1.5, P(x) = 0.1, not 0.15.

@johnc3526 8 жыл бұрын

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

@roseb2105 7 жыл бұрын

So is this basically the same as weighted average

@robbiedunne8170 5 жыл бұрын

How did you get the count to get P(x) of profits?

@amilinenisravan 4 жыл бұрын

How did you get p(x) in Terrific Taco?? i think frequency count is missing

@sunilkumargupta7980 6 жыл бұрын

Can you refer me the 1st playlist link

@trindamartinwolfe9554 5 жыл бұрын

When I add the results of X x P(X), I keep getting 3.92, not 3.70....?

@sulabh87 3 жыл бұрын

3.92 is correct

@adityachintalapati2191 2 жыл бұрын

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.

@zzznoname5571 5 жыл бұрын

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?

@vulnerablerummy 5 жыл бұрын

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).

@euginelutta 2 жыл бұрын

Hello,I have a question. How did Brandon arrive at the count as 5,10,11,44 and 38.Or it was an assumption

@RT-py5sh 7 жыл бұрын

what is the difference between expected value and the arithmetic mean???

@VillegasCar 7 жыл бұрын

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

@fatriantobong2097 2 жыл бұрын

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

@areeahiantab1908 2 жыл бұрын

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

@sydellefelicien1043 8 ай бұрын

The expected value for the class satisfaction problem should add up to 3.921

@engineerkhan9828 5 жыл бұрын

I want these slides, can you send me plx?

@galibkhan4418 8 жыл бұрын

wow.

@max_paynetothemax9499 4 жыл бұрын

minor error 19:06 it should 1.5 * .10 instead it's 1.5 * .15 at fifth row.

@areeahiantab1908 2 жыл бұрын

i meant the 1.5 column

@Maria-hx7ix 8 жыл бұрын

I think the expected value for class satisfaction should be 3.921. Or I've entered an alternate universe

@inkyinkblot 8 жыл бұрын

.046+.186+.306+1.628+1.755 = 3.921....

@MsJulie711 8 жыл бұрын

@BrandonFoltz 8 жыл бұрын

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!

@francescocommisso5352 9 жыл бұрын

An 87 is an A...

@JJony123 9 жыл бұрын

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.

@BrandonFoltz 9 жыл бұрын

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.

@LondonPhD 9 жыл бұрын

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...

@harshalshinde227 8 жыл бұрын

+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