I second that!

Extrapolation is actually necessary in certain circumstances though - for example predicting growth of global human population, economic forecasts, environmental forecasts regarding climate change.... anything that has to do with the future.

Post hoc ergo propter hoc!

SilortheBlade Makes sense to me

Pfhorrest Or it could be that people who have endured a Nicholas Cage movie are more likely to drown themselves ...

That's true, but the data shows a close correlation over multiple years, not just over the seasons of a given year. It just so happens that the summers of years with more Nicholas Cage movies also happen to have more drownings.

lol. Well, probably.

The video explains that it's not because two elements are correlated that one is the cause of the other. One '''can''' be the cause, but it's not logical to imply it just from their correlation. It was not the floor itself that broke the glass even though it is related to the breaking, it was it's impact with the glass, '''caused''' by gravity.

XKCD is a pretty good comic :)

Kachimbo somebody missed the joke

Herodotus Von 8428 no, someone got the joke, but felt the need to expand our knowledge.

psst. its vice versa, not visa versa

and if they're not connected then they DON'T CORRELATE. this shit's a red herring.

@@improover113 talking specifically about causal relationships, as the phrase states explicitly

EasySnake 100% agree

i've seen this too! It irks me to no end.

This is crash course statistics and statistics is all about probability?

Islam xDDDD

That's the tricky part! Ultimately they all need to be interpreted. Overall, there is no true "proof", just higher levels of confidence. I am confident that the city of Paris exists, even though I've never been there. The process generally starts by asking "is this even possible?" and "Does this make some sense?" Then you can go back and try to find some other cause of the data you got. Eventually, you have to do experiments carefully. But even well-planned experiments can have hickups and biases (there have been many cases of seemingly high-confidence experiments not being repeatable by other professionals). Often, multiple experimenters need to come up with the same results on their own (and usually with their own equipment) before the scientific community is convinced. Overall, it's a difficult and time consuming process.

In health data like the lung example, there is a set of criteria called the Bradford-Hill criteria. Google it. This is criteria for determining if something can be considered causation. It is not a checklist: you still need to do your own scientific interpretation. But it’s a good way to get an idea of whether the data your looking at implies causation or not. The criteria are: effect size, consistency, specificity, temporality, biological plausibility, dose-response relationship, coherence, analogous results. Interestingly, Bradford Hill who came up with this list, is the same Hill who co-authored the original Doll and Hill paper that established the linked between smoking and lung cancer!

Squares of real numbers are always nonnegative, by definition. They can never be less than zero -- the square of -5 is 25, for example.

It doesn't really matter either way. The general consensus is that the last letters from the latin alphabet, i.e. x, y and z are being used as placeholderds for unknown quantities, whereas letters from the beginning (e.g. a, b and c) or middle (e.g. k, l, m and n) are being used as placeholders for known quantities (to be supplied or deduced when doing a specific example). The placeholders for know quantities may be different in different countries for many reasons (ease of pronounciation, legibility, tradition, etc.). Tradition usually also means that often the same equation uses different placeholders in math and physics. Example: in Math class the may use y = ax + b, in Physics class they may use y = mx + c, just because ... (and then of course in the kinetic equations this becomes e.g. v = at + v0 representing physical quantities).

I am also looking for that :/

Sango, that's a good tip. But I fear that addressing people as the "scientifically illiterate" might not be the best way to get your message across. (What I would give for Crash Course: Rhetoric).

Everyone was illiterate (scientific and otherwise) at one point. It is one's duty to make sure they do not continue to be.

There is no causation only chaos.

It is absolutely true that everyone begins illiterate, and there should be no shame in that. However, referring to people as such can cause them to misinterpret your message as being condescending, even though you had no intention to be that way. Regardless, they are now slighted, and in retaliation, they ignore your advice, no matter how reasonable it was.

kaizersabre, there is no Dana, only ZOOL.

Child Fs but why

Ok, you talked me into it.

containing the word EVERYONE in caps lock

yes

Phony Aardvark i learned it as y= ax+b

Bryan, what does m stand for? The mmmslope? (I actually don't know the answer, now that I think about it)

O_O *head-explosion*

I know it was c (at least in my part of the world)

"mx + c" is also reasonable in the sense that "c" is often used to refer to some "constant". This is also the explanation for e=mc^2. Because the speed of light in a vacuum is a constant.

(For those who have the same problem: "Old Faithful" seems to be the name of a geyser. (I don't know where it is, but when an English KZfaq show refers to a location, person, event or sports ritual you have never heared of, you can be pretty sure it's in North America.)

I think it requires an experimental study

optimum angle for maximum range. Range in terms of angle would have a turning point around 45 degrees where it reaches its max range then goes back down. one example

you can use a parabola to fit data. It would be polynomial regression where your x's are taken to various powers. Sometimes it's really useful to do so, since often data isn't perfectly linear.