Statistics in Schools – Answering the 3 Questions of Statistics Using a Picture

Statistics in Schools – Answering the 3 Questions of Statistics Using a Picture


[MUSIC] Alright, so all of
statistical analysis boils down to three questions,
and I have laid the claim that while math can answer
these three questions, you can use a different method. If you have the right picture, you can answer the three
questions; How big is it? What difference does it make? And are you sure that’s
not just dumb luck? So, let’s go to the
board for an example. OK, it’s 1854 and people
are dropping like flies from Cholera, in England, in
London, in the Soho district. A lot of people are dying,
very, very ugly way to die, you don’t want to die
from Cholera…trust me. But, it’s 1854 and I don’t even
have a germ theory of disease, I have no idea what causes it. The most popular
theory is miasmas, which is to say, bad smells. And there is one guy, named
Snow, who was a physician at the time, and he
said, you know what? If it was bad smells, everyone
down wind would be a goner, and I’m not seeing that,
so I don’t think it’s air. [BUZZER] Which leaves, because I don’t
really know about bacteria yet, that leaves bad water, bad food. I’m thinking it’s not
the bad food thing, I’m gonna go with water. [DING] So, where do people
get their water? People get their
water from a well, because there’s no
indoor plumbing yet. So, Snow made a map, he took
a map of the Soho district, which basically, you know,
a bunch of cross streets like that and he just added… [WHOOSH] …deaths. So every household that had a
death he put one pip for deaths, so there’s some deaths
here, some deaths here, deaths all over the
place, a couple out here. Alright [WHOOSH] so he’s got this death map and then he says I
think it’s the water so I’m gonna add
where the wells are. It turns out there’s a well over
here, there’s a well up here, there’s a well down here,
there’s a well right there, a well down here and there’s a
well right here.That’s the Broad Street pump. [WHOOSH] And he said, you know what? I think there might
be something wrong with the broad street well. And he talked to the city
elders and he convinced them and they disabled the pump. They took the handle off and
people had to go elsewhere to get their water
and they stopped dying [GUITAR] So, that seemed to be
pretty good evidence. So OK, let’s take a look
at our three questions. How big is it? He has clearly demonstrated
how big the problem is, so we’re answering
how big it is. So, second question, what
difference does it make? Well, if I live far away
from the Broad Street pump, I seem to live and
if I live close to the Broad Street pump, I die. So, that’s kind of an
important difference. Ok, so we’ve got meaning, we’ve got what difference
does it make covered. Third question, and are you
sure that’s not just dumb luck? And this is the tricky
one, this is the one that usually takes
a lot of math, but this time, what did he do? He took a look at his map and he noticed there
were some outliers, there were some changes
in the pattern. The first one, is he noticed
right around here is a section where it’s close to the pump,
but there were no deaths and there was something
similar going on over here close to the pump but no deaths. And then out here, far away from
the pump, a couple of deaths. First thing he did, he went and
knocked on the door and he said, hey, what’s going on here? And they said, well, the
mistress of the house died and so did her niece,
those are the two deaths. And he said, well, where
do you get your water? And they said, well, the
mistress of this house tended to like the taste of the water
from the Broad Street pump, so every morning they had
us walk to Hell and gone to go get it for them. And so, um, yeah,
that’s why she died. And her niece also died
because her niece was allowed to drink, “the good water”. All the servants in the
household, they weren’t allowed to drink the, “good water” that
tasted better, so they lived. And then over here he
knocked on the door and he found out,
it was a brewery they weren’t drinking the
water…and they had their own well. But, the point was, their
not drinking the water from this pump, so, they live. And over here, knocked
on the door, [KNOCKING] it was a work house, which was
a little bit like a prison, and so the people weren’t
really let out as much as you’d like and, they had a well
inside there as well. So, he had positive outliers,
people who were living far away from the Broad Street pump, but died because they
were drinking the water from the pump. And he had people
who were living close to the Broad Street pump,
who didn’t drink the water from the pump and they lived. So, you live close
to the pump, you die, unless you don’t
drink the water. You live far away from
the pump, you live, unless you do drink the water. Pretty sure it’s the water. [DING] And that’s how, in 1854, before
we understood about bacteria, before anybody knew
about viruses, before we could understand
any of that, a statistical analysis
showed the cause of Cholera. It’s the water, [DINGS] and it was done with
the right picture. [MUSIC]

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