Random Variables and Probability Distributions

[@bonggenie3611]

"How are you paying today?" Me: "Goat"

[@nysadelosreyes6844]

Bong Genie LMAO

[@Lulululuc]

indeed _the best way to pay_

[@lakshita1408]

you explained it better in 4 minutes what my professors couldn't in hours. Thank you for simplifying the concept and making it interesting.

[@DrNic]

Glad it helped!

[@DrNic]

In order to make money we had to restrict access to some of the videos. Email me at [e-mail] and I'll give you access to the ones we have finished. The script for the video about the normal distribution has been written, so the video should be up in about a month.

[@biggykwon9648]

How did you find the value of P(X=x) . What did you do?

[@abrohamproductions8263]

Luke is the most serious ice cream man I've ever seen. 😐🤔

[@DrNic]

Ice cream selling is a serous business. Those cones keep breaking and people try to pay with goats!

[@RMatt2016]

@@DrNic unfortunately, type of payment cant be measured with random variables!

[@ASHOKKUMAR-jm6yn]

I just love the way u make things easy.... Lots of love from India

[@hongyunxu6018]

Best explanations that I've seen so far, thank you!

[@danascully1248]

1:18 bruh is that Mello from Death Note?

[@DrNic]

Maybe…

[@rishi680]

*My **B.tech** completed but did't undersatand little bit about random variable,but today i saw this video, and it seems it is too easy bcz of you only,thanks mam*

[@DrNic]

I didn’t understand either for years until I had to teach it. It really isn’t tricky, but somehow we just don’t get it

[@ianjaydelosangeles3173]

very well presented video! u earned a subscriber maam.

[@curiouscraw3927]

I have discovered your channel minutes ago and already know that those brilliant lovely videos are going to help me survive my stochastics exam - thanks a lot and lots of respect for your work! I really appreciate the details in your videos - the dragon card game, the fact that the ice cream guy has a cochlear implant... amazing! Best wishes!

[@DrNic]

That is great to hear. We try to be inclusive of different ethnicities and wanted to include a disability - thank you for noticing!

[@Tlianscom]

quit easy to understand even for beginner.. keep it Ma'am

[@felizijaime1655]

That is the best explaination I´ve ever seen. Thanks!

[@danielmwangi4308]

The videos are of very good quality and very informative. They are a great resource for both learners and educators. Thank you.

[@naeemurrahman8767]

Love your video and the method through which you've explained everything.

[@md.hasanuzzaman1956]

Dr. Nic...Awesome...Magical explanation...Thank you so much

[@sattikbiswas2187]

Awesome Video. Thank you so much ma'am.

[@Ferdinaand]

Excellent explanation & animations. So necessary to solidify the basics to take things further.

[@rishabhdude6750]

this videos is fab and mam you teach awsome

[@DrNic]

rishabh dude I'm so glad you like it.

[@mnhlhmo7967]

Please answer my question Why we use the term (random variable), if we do a study we determine the variable of interest firstly (such as, body weight, blood pressure). So, what is the difference between (study variable) and the (random variable). Thanks in advance

[@DrNic]

I am not familiar with the term "study variable", but I can see what it means from what you are saying. I would say that study variables are random variables. But not all random variables are study variables. Random variable is a name for a concept. Ask some more if this is not clear yet.

[@mnhlhmo7967]

@@DrNic Thank you very much What I mean by (study variables) is in any study we collect data in term of variable (The characteristics we measure are called variables). Now, is there any difference between (study variables) and the term (random variable).

[@DrNic]

A study variable is a specific instance of a random variable. You collect data in the form of values that the variable takes in order to find a theoretical model for that random variable.

[@giselegiram]

Great explanation, all your videos are really helpful. Go Statistics Learning Centre!! Thanks.

[@vikasmeenaofficial]

THANKS ......you are a great teacher

[@josephif]

you spoke about ethnicity as a not a random variable say if i categorize it to different form of ethnicity as 1 ,2 ,3 4 can I consider ethnicity as a random variable ,just started learning probability and also goes to marital stause can it be easy to call married as 1 and not married as 2 and do the random variable stuff and its distribution

[@ajayhemanth]

Amazing Video ! Best explanation for - WHY RANDOM VARIABLE is needed ... Thank you for taking pain to make such a fabulous video ...

[@DrNic]

Thanks - I had the same problem when I was first working out what a random variable was, so I'm glad it helps you.

[@checilleabitria3356]

very clear explanation! thanks a lot maam.

[@eduardosa9658]

Great work! Finally some basic explaination you can apply Statistics to gain some money in real thing and not to lose money in gamble statistics. :D

[@DrNic]

Glad it was helpful!

[@SafirahOnafeko]

Please what is the difference between a discrete random variable and a non random variable,I got confused with the two when attempting your exercises

[@ibrahimswaray7459]

Best explanation ever.

[@DrNic]

Thanks

[@k.c.krishna9570]

U helped me in my frm preparation.thankyou

[@xueyeelee4512]

amazing explanation!!! im clearly understand what you are teaching in the video with a simple and interesting example!!

[@DrNic]

Glad it was helpful!

[@hole01]

Dr.Nic, Thank you very much. Just one question: I'm not sure if the number of ice creams ordered by a customer is random. Given that ice cream melts and most people would only buy one or two unless they were throwing a big party, I don't think this is a random situation. Could you please elaborate? I agree that this is a much more entertaining example than the traditional coin toss.

[@DrNic]

Mostly people buy one or two ice creams, but a family of four would generally want four ice creams. Having said that, that is not what random is about. A random variable can take a range of values and we have some idea about what values they can take and how likely the different values are. Random does not mean any number at all. THis might be useful: creativemaths.net/blog/random-meaning/

[@giangnguyen-cp2vo]

thank you so much for helping me to understand these kind of things

[@tsuki6230]

Awesome video. Thanks

[@berkmehmet2399]

Sorry but if categorical variable (I.e marietal status) are transformed to numerical ones, they could be counted also as random variable? Dont they?

[@raghavmoar3211]

Thanks for letting know what cannot be a random variable

[@DrNic]

Happy to help. Sometimes it is more important to know what a category excludes as well as what it includes.

[@littlelilly7480]

for marital status we can use random variable right like for married 1 and for unmarried 0

[@DrNic]

You could, except there are more categories than those and you can only use the number as an indicator, not a value.

[@littlelilly7480]

@@DrNic thank you for clarifying it, such a unique way of teaching data science, love it

[@somcana]

qualitative variable are not considered random variables? Is that accurate understanding? I thought you can still do distributions with them but not probability?

[@DrNic]

You can call qualitative variables random variables, but at this level it's not much use as you can't use them in mathematical formulas etc.

[@suchitrakulkarni4559]

Beautifully explained!😍

[@DrNic]

Thanks a lot 😊 I found the concept difficult when I first learned it so I can understand how others might struggle.

[@akshatjoshi391]

Thank you for not bringing in a fair coin. Video was very helpful :)

[@DrNic]

I hear you! So sick of coins, dice and balls in urns!

[@z.r1999]

OMG ...! Great video Mam

[@DrNic]

Thanks a lot 😊

[@jimmyhaotran123]

Great explanation. Just want to add that the first example of cakes and bananas, could be random variables if you assign specific numbers of each specific case.

[@DrNic]

You need to be careful how you phrase this. If you are counting how many cakes or bananas over several events then this could be a random variable. If you assign a code number such as 1 for cake and 2 for banana, then this is not a random variable.

[@DrNic]

@Semhar Yohannes You could have a random variable for the number of bananas or the number of apples. If you arbitrarily assign code numbers you cannot perform operations on them. One way I check is to say, would it make sense to find the mean cake? or the mean fruit? Your numbers 0 and 1 are not just code numbers, they are a measure of how many heads you have flipped.

[@minimaxPFC]

You said that we can not use random variables to model the type that customer use to pay ice cream, but if we assign 1 if it's payed by cash, 2 payed with card, can we then use random variables?

[@DrNic]

Nope - the numbers do not mean anything, but are arbitrarily assigned. You cannot add them together, for instance.

[@SuperDananjaya]

Ma'am, you answered a number of questions, I was looking forward the answers for! Great!

[@DrNic]

Glad it was helpful!

[@vijayashekhars.s9421]

Nice Video..

[@iidtxbc]

Thank you for the video! I just wonder what could the sample space be for the ice-cream sales example?

[@shamanthks7218]

S = Number of ice creams bought by customers in a single visit. S = {1, 2, 3, 4, 5, 6}

[@Gia-Gia]

Thanks for your lesson, it's very useful and easy to understand

[@DrNic]

Glad to hear that. I found the concept difficult when I first learned it, so I wanted to make it easier for other people.

[@mlem7108]

Hi Dr Nic, Thanks for your videos. My lecturer said random variables are a mapping of all possible outcomes to real numbers. Can't we map stuff like colour or marital status to numbers? Like, marital status would be a Bernoulli trial (I think) and for colour we could use numbers to label them like Red Green Blue on a computer (another example of a continuous random variable?). Thank you very much.

[@DrNic]

Strictly speaking you can have nominal random variables, such as colour or marital status, but it is not usual to call them random variables. The point about random variables is that the numbers make sense, and that it makes sense to find, for instance, the mean or expected value of the random variable. If the numbers are arbitrarily assigned, they are not random variables. I'm not sure what your lecturer is referring to.

[@ajaykharat8689]

Hi Dr. Nic, This is my first comment on KZbin. I found your entire series on statistics so easy to understand, crystal clear and engaging. I would like to thank you for :- 1. Great effort. 2. Nobel work. Thanking you on behalf of 1.35 billion Indian . You should have some teaching sessions in India. If possible try for it.. And lastly most important you are gorgeous...

[@tidalfriction5301]

Savior!!! THANK YOU THANK YOU!!!!

[@DrNic]

Most welcome

[@buglaudonglai9728]

Great video! It helps me a lot.

[@RushiLadani1995]

but can we not measure the method that the customer is paying us in and their ethnicity. Can wealso not measure the type of topping that they choose ? I think we can.If I can, does that make them a discrete random variable ?

[@DrNic]

Things like the method and ethnicity are categorical measures that do not have a quantity associated with them. For example method would equal cash or credit card, and ethnicity would equal European, Asian, Pasifika etc. These are not numeric values, and thus are not random variables. We can record these values, but they are not something that has a numeric measure. You might like to watch our video about types of data to clarify this.

[@maryamnizami7746]

@@DrNic Hello maa`m, but won`t they become random values if we assign them a discrete value, like in case of coin toss our random variable becomes X={ 1 if heads, 0 if tails, now if we model the payment method in such fashion Y = {1 if credit card, 0 if cash , then will it become a random variable? Thanks

[@askariaziz4163]

Thank you very much for the video it was so helpful in developing my understanding.

[@GatewayTOEM]

I got 7/7. This is because you explained it well.

[@DrNic]

Good for you. I think questions help people reinforce their learning

[@igniters5146]

does play a certain lottery by buying one ticket per week a random variable?

[@DrNic]

The amount the ticket could win is a random variable.

[@amrabdelhakim1585]

can you please explain why the color of a tulip flower is not a random variable?

[@DrNic]

Usually random variables take numeric values, whereas the tulip colour is not a number. If you had four tulips then the number of pink tulips out of the four would be a random variable.

[@amrabdelhakim1585]

@@DrNic In my sick mind I somehow assigned numbers to colors and wondered why are the colors not represented by a random variable. Thank you Dr. Nic

[@irismo6566]

very great explanation thx

[@DrNic]

Glad it was helpful!

[@simran_kaur963]

fabulous m glad i find your video

[@abhisheks5625]

Got the concept and the answers correct.

[@DrNic]

That's great

[@GerritParker]

So Awesome! Thank you.

[@DrNic]

THanks

[@Lejhand10]

well explained ! Thank you

[@DrNic]

Happy to hear it

[@PlacesWeveBeen]

Very helpful explanation. Thank you!

[@MayankRamnani1802]

Great Video! Can we assume that random variable concept comes under empirical probability (experimental) as the probability here is based on past outcomes (and events are clearly not equally likely) or it can be used under axiomatic approach also?

[@DrNic]

The concept of a random variable applies to all probability, regardless of the source of the model (experimental or theoretical/axiomatic/a priori. A binomial distribution is a theoretical model, as is a normal distribution. Sometimes data from historic values form a better approximation of the future than a theoretical model. You might like to watch our video, Probability 1 for a fuller description of that. Equal likelihood is not really an issue either way.

[@mahmoudfathi8249]

Finally I like statistics :D

[@umadevi8125]

Super teaching

[@leraheva8485]

Great job on explaining Random vAriables.

[@DrNic]

Thanks - I've taught it quite a few times and know what makes it difficult for most people.

[@masterzoruko9680]

How did u get ur P(X=x)?

[@JoJo-il3qe]

Thanks it's so useful.pls share vdo about booles inequality

[@curiouspuzzles3098]

When are the other videos coming up?

[@REEMA-mo3hf]

Such a great video thank you so much doctor Nick♥️♥️♥️♥️

[@DrNic]

You are so welcome!

[@dekkunYT]

1:30 can someone teach me how that frequencies was defined. Our exam is tommorow pls help tnx

[@DrNic]

In this example the probability distribution comes from historical data. Each probability is the number of customers who bought that number of ice creams divided by the total number of customers.

[@dekkunYT]

@@DrNic thank you so much I am done studying now :) thanks a lot again. God bless you Madam

[@riddle-me-ruben]

Why is marital status not a random variable? If the sample space is married or unmarried, {M, N}, we can assign the random variable X to be 1 if the couple is married, and 0 if unmarried, so that X(M) = 1 and X(N) = 0, hence a Bernoulli random variable.

[@natdeu]

Thank you so much for this video!

[@jeniferseighman]

great vid fam

[@xuanquangnguyen2291]

So great video, thank you so much

[@DrNic]

You are so welcome!

[@btssuejibae8130]

why is the length of the stem of the tulip not discrete?

[@DrNic]

The length of a tulip stem is measured and can take a continuous range of values. For example it could be 230 mm or 231 mm or 231.5 mm or 200 mm etc. Discrete variables are usually used for when we count things rather than measure them. So number of tulips would be a discrete variable.

[@btssuejibae8130]

@@DrNic i figured it out now 😅 but thank you so much for responding!!

[@DrNic]

All part of the service!

[@queensaharaice7376]

250% better than Khan academy ad Wikipedia.

[@DrNic]

We like to think so! ;)

[@Privacy-LOST]

How many cones can one get for a goat ?

[@stephanie_ong]

great video!

[@ahmedmjhool4822]

Cool Beans!

[@Privacy-LOST]

I was the 1000'th like for this video. How Random is that...

[@suhadandis9383]

Thank you

[@santhoshnaidukoribilli]

superb

[@DrNic]

Thanks 🤗

[@shaikabid652]

Your underrated

[@DrNic]

Thanks. Tell your friends and maybe that will help me get more views.

[@WishachieverZ]

thank you so much for the help I understand now!! and if you are the one on videos your funny with your animations jaja. thank you

[@amirajemlymaranan9016]

can i get a transcript of this vid?

[@DrNic]

Email me at [e-mail] and explain what you will be using it for, and I will be happy to send it to you.

[@sathyanarrayananbalaji8401]

why not flavor topings ?

[@DrNic]

Generally we use the term "random variable" for something that takes a numerical value. When the question is "what topping do you prefer?", the answer is a word, not a number.

[@nilanjanbiswas844]

+Statistics Learning Centre So nice way of teaching....Not only i learned but enjoyed.... Thank you Mam....😊👍

[@naveenrajr1793]

Thank you Mam

[@selinacamina1177]

thank you for this!

[@DrNic]

You're so welcome!

[@shawnmarquez6714]

you make me smirk

[@shawnmarquez6714]

yes sir!

[@043mehdi]

4:44 hawking approves

[@yogitashinde5475]

Mam please teach Markov chain

[@DrNic]

I will bear that in mind. I've always enjoyed Markov chains.

[@venumadhavmenday132]

Thank you, Dr. Isn't marriage status a random variable (binomial)

[@venumadhavmenday132]

I meant bernoulli

[@DrNic]

In most cases it would include married, never married, divorced, widowed, and then you get to civil union etc.

[@vaibhavpratapsingh9956]

the answer of two people being married could be true or false so won,t we consider it as discrete random variable

[@DrNic]

You could call it a nominal random variable if you were being very strict about it. However you cannot do any numerical operations with the value of married or not, so you would not usually call it a random variable.

[@Ryugaa007]

Checking marital status is not a random variable. .. why ??

[@DrNic]

It is not a numerical random variable, which is the usual interpretation for a random variable.

[@tellmeyourwish]

Thanks a lot! :)

[@rameshaafridi3050]

amazing

[@shaikabid5311]

thank you mam

[@srinivasp662]

Thanks.

[@johnnguyen3115]

good

[@rudrashukla9220]

awesome ...

[@g7sky]

how can 225 customers buy 1 (same) ice cream ? who will get the ice cream ?

[@ahstudios8417]

225 customer buy 1 ice cream each

[@g7sky]

thanx got it