Correlation Doesn't Equal Causation: Crash Course Statistics #8

Today we’re going to talk about data relationships and what we can learn from them. We’ll focus on correlation, which is a measure of how two variables move together, and we’ll also introduce some useful statistical terms you’ve probably heard of like regression coefficient, correlation coefficient (r), and r^2. But first, we’ll need to introduce a useful way to represent bivariate continuous data - the scatter plot. The scatter plot has been called “the most useful invention in the history of statistical graphics” but that doesn’t necessarily mean it can tell us everything. Just because two data sets move together doesn’t necessarily mean one CAUSES the other. This gives us one of the most important tenets of statistics: correlation does not imply causation.

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[snowballeffect]

This needs to be mandatory viewing for EVERYONE.

[sugami]

"Correlation does not equal causation" was my old stats teacher's favourite phrase along with "always interpolate, never extrapolate." :)

[Pfhorrest]

Nicholas Cage movies are correlated by yet another unmentioned variable: summer. Nicholas Cage is an action movie star. Action movies are generally targeted for summer releases. Summer is also hot, which is the cause behind air conditioner sales and swimming, the latter of which is of course the cause of drowning.

[SilortheBlade]

Bah. I know my rock keeps away tigers because I have never seen a tiger for as long as I have had it.

[murphygreen]

This has been my favorite CrashCourse season by far. Really enjoying the material and the host!

[aude]

A class on non linear relationships would be FANTASTIC :) And more classes in general (e.g., on general versus mixed effects models; GAMs etc...) Thank you for your dynamism!

[qilinxue]

*Me:* I used to think correlation implied causation.

*Me:* Then I watched this video. Now I don't.

*Friend:* Sounds like the video helped.

*Me:* Well, Maybe.

[laterkater]

Better explanation then my university level stats class. 👍

[Deedj]

Everyone needs to see this! Just because things seem connected on the surface doesn’t mean they’re related and Visa Versa!

[BlackCatGodess]

Puppy cat! I didn't know that they'd made a stuffed animal of him. This has greatly improved my day.

[jesusosegueda]

Crash Course, thank you so much. This awesome course is definitively above the curve!

[greyareaRK]

I haven't watched Nicholas Cage movies, AND I haven't drowned. Aha!

[akankshaandadityasingh]

When she apologises for using imperial

[aaronmarks]

"Air Cons, and Con Airs"

Amazing

[earthellie]

“Mr. Fluffy misses you.”

*pouts thinking of the cat I don’t have missing me*

[KASSISHOT]

Every time I see one of these videos I look at the view count and know that there's that many more people out there that are better educated about this topic and that makes me very optimistic for the future keep up the great work guys

[easysnake]

I feel some people go so far in this argument that they seem to argue the correlation disproves causation.

Eg. "thats only correlation it doesnt prove causation, obviously you are wrong"

Yes correlation doesnt prove causation, but it most definitely does not disprove causation. Further it might suggest causation, or that a 3rd factor is causing both phenomena to occur. Its frustrating to give data in an argument, to have the other side counter with, "thats only correlation, it doesn't prove causation, you are wrong."

[mielthebee]

"..if people blink more when they're lying!"

Our Professor: 😳

[aaronmarks]

I wish all my scatterplots ended up making pictures of dinosaurs.

[wenhong]

Watching this video at work, miss my cat. Burst into tears