Probability is not Likelihood. Find out why!!!

Here's one of those tricky little things, Probability vs. Likelihood. In common conversation we use these words interchangeably. However, statisticians make a clear distinction that is important to understand if you want to follow their logic. The good news is that they are both super simple. The bad news is that they are easy to get mixed up. The StatQuest gives you visual images that make them both easy to remember so you'll always keep them straight.

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[suivzmoi]

probability is the quantity most people are familiar with which deals with predicting new data given a known model ("what is the probability of getting heads six times in a row flipping this 50:50 coin?") while likelihood deals with fitting models given some known data ("what is the likelihood that this coin is/isn't rigged given that I just flipped heads six times in a row?"). I wanted to add this perspective because using the example in this clip, a likelihood quantity such as 0.12 is not meaningful to the layman unless it is explained exactly what 0.12 means: a measure of the sample's support for the assumed model i.e. low values either mean rare data or incorrect model!

[BulkySplash]

I am a postdoc in neuroscience/psychiatry on a mission to brush up my stats knowledge. I can only repeat what others have already said: It's amazing how you break down and explain complicated topics in an understandable way. Thx so much for these videos.

[patheddles]

Right, so:
- Probability is for predicting an outcome within a known system (eg. rolling fair dice)
- Likelihood is for analysing an outcome when the system is not known for certain (eg. determining if particular dice actually are fair, or determining what curve is the best model for a dataset)

I just learned a thing - thank you. :-)

[zerosiii]

Seriously, please don't stop making these! You really nail the topics in the most perfect time, and always explain them in awesome ways :)

[elderhiker]

This is good stuff. Although I have taken 3 graduate level statistics courses, I struggle to explain the rationale behind the concepts. Which means, of course, that I lack deep learning of statistics. Your straightforward and graphic explanations are marvelous; even better than my stats professors. Thanks and I’m a subscriber now.

[graymars]

After spending 2 hours on YouTube learning about probability and anything related to it, I landed on this video and I want to say this: I LOVE YOU

[Hamromerochannel]

I never thought I would be saying I like stats. As you grow older, you will see the importance of stats in the real world you start to appreciate it more

[mastermike]

Your intro songs have really grown on me. You are like the Bob Ross of Statistics.

[skandagurunathanr]

I was completely confused on the concepts, after referring lots of videos and confusing intuition I just came to this channel. The song you play at the starting of this video just refreshes the learning journey. The content you give with clear intuition makes me really very very very very very happy...

[rmmkxmw]

this is the most understandable explanation out of all videos i've seen so far about the differences between probability and likelihood.. thankyou so much

[abdallahbahyabdelazimothma]

wow!! that was the most clearly explained math video i have ever seen, thank you so much

[sannwailhyan]

I studied financial econometric for past two semester, now I am at third semester, doing special project/thesis, all the concept I studies, becomes linked after I watch your video, I just want to say I really appreciated your explanations. I am pressing likes for every videos I watch going forward. Maybe after my project, I will learn machine learning. Thank you.

[gurditsinghchandok]

came here after watching his logistic regression vids..the clearity of these topics is insane!! thanks a lot :)

[Stew]

Wow and gosh! I work a lot in risk management and have long argued for the appropriate use of the terms 'likelihood' and 'probabiltiy'. As far as most poeple are concerned, they are synonymous. People cannot understand the difference between the likelihood of a specific event and the probability of an event causing a specified outcome. Thanks for the simplification.

[MadhushreeSinha]

statquest makes feel very very very happy indeed!

[EnlightenNook]

I was trying to understand likelihood from yesterday but unable to understand properly, this the best video which explained me in very simple way.
Thanks

[sarrae]

StatQuest, you're the best when it comes to "making it Simple"

[becauserocks.]

Duuuude, I've been doing data science for about 5 years now and stats for a lot longer and this is the best explanation every. I'm stealing this!

[sarthakdua]

Crisp, concise and to the point! Instantly cleared my confusion!

[mostinho]

The likelihood of a specific data point (measurement) is the value of the pdf at that specific data point. (Values on the x axis and pdf/likelihood on the y axis)
The probability for any specific exact measurement point, is 0 but probability of a range is the area under the pdf in that range
The probability is of data given a distribution where as likelihood is the likelihood of a distribution given data.