Random Variables and Probability Distributions
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- čas přidán 2. 08. 2024
- The idea of a random variable can be surprisingly difficult. In this video we help you learn what a random variable is, and the difference between discrete and continuous random variables.
0:00 Introduction
1:13 X is defined as the number of ice creams a customer orders
1:30 Historic data is used to estimate the probability of each number of ice creams
1:50 The distribution is graphed, find P(X=1) etc
3:07 Examples of discrete random variables, not random variables, and continuous random variables.
4:13 Quiz to check your understanding
This video leads on to other videos about random variables and distributions:
Discrete random variables: • Discrete Random Variab...
Probability distribution models: • Probability Distributi...
The normal distribution: • Understanding the norm...
The binomial distribution: • Understanding the Bino...
See creativemaths.net/videos/ for all of Dr Nic's videos organised by topic.
#DrNicStats #Statistics #Probability
"How are you paying today?"
Me: "Goat"
Bong Genie LMAO
indeed
_the best way to pay_
Best explanations that I've seen so far, thank you!
The videos are of very good quality and very informative. They are a great resource for both learners and educators.
Thank you.
I just love the way u make things easy.... Lots of love from India
Love your video and the method through which you've explained everything.
you explained it better in 4 minutes what my professors couldn't in hours. Thank you for simplifying the concept and making it interesting.
Glad it helped!
Excellent explanation & animations. So necessary to solidify the basics to take things further.
Great explanation, all your videos are really helpful. Go Statistics Learning Centre!! Thanks.
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!
That is great to hear. We try to be inclusive of different ethnicities and wanted to include a disability - thank you for noticing!
Dr. Nic...Awesome...Magical explanation...Thank you so much
Luke is the most serious ice cream man I've ever seen. 😐🤔
Ice cream selling is a serous business. Those cones keep breaking and people try to pay with goats!
@@DrNic unfortunately, type of payment cant be measured with random variables!
Thank you very much for the video it was so helpful in developing my understanding.
Amazing Video !
Best explanation for - WHY RANDOM VARIABLE is needed ...
Thank you for taking pain to make such a fabulous video ...
Thanks - I had the same problem when I was first working out what a random variable was, so I'm glad it helps you.
quit easy to understand even for beginner.. keep it Ma'am
That is the best explaination I´ve ever seen. Thanks!
very clear explanation! thanks a lot maam.
amazing explanation!!! im clearly understand what you are teaching in the video with a simple and interesting example!!
Glad it was helpful!
Very helpful explanation. Thank you!
Awesome video. Thanks
Thank you so much for this video!
Great video! It helps me a lot.
thank you so much for helping me to understand these kind of things
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
Glad it was helpful!
very well presented video! u earned a subscriber maam.
Ma'am, you answered a number of questions, I was looking forward the answers for! Great!
Glad it was helpful!
THANKS ......you are a great teacher
Best explanation ever.
Hi Dr. Nic,
This is my first comment on CZcams.
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...
Nice Video..
fabulous m glad i find your video
this videos is fab and mam you teach awsome
rishabh dude I'm so glad you like it.
Awesome Video. Thank you so much ma'am.
Thanks a lot! :)
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
Savior!!! THANK YOU THANK YOU!!!!
U helped me in my frm preparation.thankyou
Thank you
Great job on explaining Random vAriables.
Thanks - I've taught it quite a few times and know what makes it difficult for most people.
great video!
Thanks it's so useful.pls share vdo about booles inequality
Thanks for your lesson, it's very useful and easy to understand
Glad to hear that. I found the concept difficult when I first learned it, so I wanted to make it easier for other people.
Cool Beans!
*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*
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
So Awesome! Thank you.
THanks
Beautifully explained!😍
Thanks a lot 😊 I found the concept difficult when I first learned it so I can understand how others might struggle.
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?
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.
awesome
...
great vid fam
well explained ! Thank you
Happy to hear it
great. thank you =]
Such a great video thank you so much doctor Nick♥️♥️♥️♥️
You are so welcome!
Got the concept and the answers correct.
very great explanation thx
Glad it was helpful!
amazing
So great video, thank you so much
You are so welcome!
Thank you Mam
OMG ...! Great video Mam
Thanks a lot 😊
Love it
Thanks.
thank you for this!
You're so welcome!
In order to make money we had to restrict access to some of the videos. Email me at n.petty@statslc.com 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.
How did you find the value of P(X=x) . What did you do?
Thanks for letting know what cannot be a random variable
Happy to help. Sometimes it is more important to know what a category excludes as well as what it includes.
Thank you for the video! I just wonder what could the sample space be for the ice-cream sales example?
S = Number of ice creams bought by customers in a single visit.
S = {1, 2, 3, 4, 5, 6}
Super teaching
thank you mam
lovely
awesome
Thank you for not bringing in a fair coin. Video was very helpful :)
I hear you! So sick of coins, dice and balls in urns!
Finally I like statistics :D
I was the 1000'th like for this video. How Random is that...
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.
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.
superb
Thanks 🤗
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.
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.
@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.
I got 7/7. This is because you explained it well.
Good for you. I think questions help people reinforce their learning
When are the other videos coming up?
thankyou ma'am.
Most welcome 😊
does play a certain lottery
by buying one ticket per week a random variable?
The amount the ticket could win is a random variable.
good
How did u get ur P(X=x)?
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?
Nope - the numbers do not mean anything, but are arbitrarily assigned. You cannot add them together, for instance.
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.
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/
you make me smirk
yes sir!
can i get a transcript of this vid?
Email me at n.petty@statslc.com and explain what you will be using it for, and I will be happy to send it to you.
you are awesome
Thank you! I do what I can.
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 ?
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.
@@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
cool
4:44 hawking approves
Your underrated
Thanks. Tell your friends and maybe that will help me get more views.
qualitative variable are not considered random variables? Is that accurate understanding? I thought you can still do distributions with them but not probability?
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.
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
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.
@@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).
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.
1:30 can someone teach me how that frequencies was defined. Our exam is tommorow pls help tnx
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.
@@DrNic thank you so much I am done studying now :) thanks a lot again. God bless you Madam
How many cones can one get for a goat ?
great video, except the "Coming Soon" videos never came!
can you please explain why the color of a tulip flower is not a random variable?
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.
@@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
250% better than Khan academy ad Wikipedia.
We like to think so! ;)
why is the length of the stem of the tulip not discrete?
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.
@@DrNic i figured it out now 😅 but thank you so much for responding!!
All part of the service!
why not flavor topings ?
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.
+Statistics Learning Centre So nice way of teaching....Not only i learned but enjoyed....
Thank you Mam....😊👍
Mam please teach Markov chain
I will bear that in mind. I've always enjoyed Markov chains.
Checking marital status is not a random variable. .. why ??
0.28 sec xD