Here is the second video for Lesson 27 RCC instruction book.
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Audio TranscriptAuto-generated
Good morning, guys.
So we're doing less than 27 measures of center on
their ability.
We're gonna start with mean today on today is Tuesday
the 31st from we doing pages to 98 to 99
we're gonna talk about mean we're gonna, um, explain what
it is in a concept way, and then we're gonna
show you how to solve how to find me on.
Then we're gonna ask some questions about what we did.
And at the end, you gonna do try a problem
to try problems on golf.
Okay, So the mean is very common in a lot
of professions, especially in teaching.
And if your scientists prior to the engineer, um, it
really means have going.
So the average in the mean are the same thing.
Um, we find average everyday as teachers, we find the
average of the classroom you remember on those veg elastic
barriers every time that you finish, which we show you.
Um, before I show you the average of the class,
um, we find the average of your greats every nine
weeks to see if you're passing or not.
We ii find the average of all your bell ringers.
Um, every nine weeks, things like that.
At the end of the year, we find the average
of all your nine weeks greats and see if you're
passing or not.
So you should be interested in knowing a little bit
about me.
Average okay any more, really is is it's a number
that represents a bunch of data.
So if you if you have these bunch of numbers
together and you want those so one you wanna representative
just one number then mean is one measure of center.
So we kind of missing and number in this center
somewhere in mill that represents thes numbers.
I said, Let's take a look at these promises.
Hana looked at the surveyor resource for being, um, well
wasted, talking about band on choir and strings from previous
pages. So if you haven't watched those videos, police force
them. Um, if you remember, Ban has a bunch of
tens. Ah, So these his money that people raised s
0 6/16 raised $10 to students raise 21 race 40
and 160 said based on these data, see things that
the average amount for the mean of these amounts of
money race by advanced ruin his $10.
So basically, she pays at the average of those numbers
beast. And we have to say, if it's what is
the mean of the man and if she is correct
and we have to explain why, yes, for why not?
So one way of thinking about average Ramin is this
idea of fair sharing thing.
And if you were so if you look at this
first line plot right here with the bunch of dollar
signs, those dollar sign means one of them means $10.
So the 1st 1 So number one has analysts.
That means that one person raised $10.
Okay, So number two's another person and raised $10 as
well. So it's a little bit different on the previous
line plot.
Okay, um, the last person number 10 raced 123456 So
that's $60.
If you remember, there was one of them that right?
60. And then one of them raised 40.
So that's number nine.
Um, if you were thes people ready of one through
10 each one is a pen.
Remember? Which one would you be?
Well, I will be number 10 because I want to
have the most money.
I mean, so I get six, No other sign, which
is $60.
But this fair shame is, Well, if I want to
know an average enemies, I want to know if I
share these with everybody and everybody has the same amount
of money.
How much?
Each one.
Okay, so if you look at these, let me make
one of the tens disappeared, and I'm gonna give it
to number one.
You know, I take another one from 10 and give
it to number two and another one and give it
to number three.
And so far until you get that, everybody gets to
the Larsen, which means $20.
That means that if everybody share the amount of money
raced, then each one will get $20.
That's one way of thinking about means.
It's not the most common way to find the mean
because it takes a little bit off, um, joining and
thinking. But these other way is the most common way.
And this is the one that everybody used some most
people used.
And these one talks about adding the data, so I
don't know those tens and others to twenties all the
sixties and forties and then dividing by the number off
values that you had.
So, in this case, if you had all these, you
get 200 because his temples templates simplest implicit.
Understand that 60 plus 20 plus train that 100 plus
4240 plus 60 200.
Okay, so what do we do with that?
200 says, divided by the total number of values.
So we've got 10 violence in total.
We're gonna divide 200.
We buy 10 on notice How they used a fraction
bar as a division.
So 200 divided by 10 is to it.
And that's exactly what we got on the previous model.
It $20 for each member dispenses some questions.
Explain how to find the mean using the first month.
Look at the first model.
That's the one that we did the fair share and
the way that we did it was we borrow it
from ah, the higher one they want.
I had the most money and gave it to the
one that had the least money.
And we found that the average once everything is shared
equally then the amount of money that everybody has for
each one had is 20.
I explained that in words, he says the model shows
that if the total Man race this year equally among
10 men, men, band members, then each person raised $20
because her to the lower size for each band members.
Okay, the number three says, Look at the second mile
it What does this 200% on 10.
And why do you buy 200 by?
So that's the one that would you did 200 waas
the sum of all the data point and then the
10 was the number of data points that you have
on. Why did we divide is because we want them
to find how much each one will get.
Not just not all 10 but each one of the
10 will get all right.
Write that down to hundreds to total amount raised.
10 is the number of band members survey and then
you fight 100 by 10 to find the average amount
of Peachtree and rates.
Okay, number four.
Well, I brought these, um, graph right here because it's
the one that we used on previous pages.
And that's the one that we that it's easier to
find out liars on this.
Next question says, are there hanging out liars in the
data? So we're still talking about the band?
Yeah, graph.
But remember, this is the previous graph.
And where are they?
What are they?
Are liars.
You remember what I liar?
You are?
I hope so.
Um, if you need an answer on the previous kugel
form and still waiting for those answers, um are liars
were numbers that don't belong to the cluster cluster will
be tens and twenties, right?
Everything is plaster or grouped around 10 and 20.
And then there was there's a 40 the 60 that
are kind of far away from the data.
Those are the out, like sporty and 60 will liars.
And then how do you know those are liars?
Because they, they don't quite belong to the to the
group. Okay, far away.
So, yes, 40 and 60 are liars because all the
other data points are 10 or 20.
The values 40 and 60 are two points that do
not quite fit with the others.
So why are we talking about are liars?
And because Sometimes you just get rid of the because
they don't Prezi represent the data.
They're just, um they it's there, like, not peace.
But then, like, I have no formalities.
OK, so you see that it's more normal to get
10th and 20 than it is to get 46.
So and when that working actors get rid of those
40 and 64 number five, let's calculate the mean without
the out liars.
Now, are we gonna divide by 10 when we add
all those will know that divide by eight this time?
Because we are taking those two out those two points
out. So if I'm hiding all the tens, I get
six. Then I had the 20.
That's 40 Sleepless party is 100 and then 100 Body
by eight will be 2.5.
So you see how it changes.
It went down from twinning, which was the average with
the out liars to 12.5 $12.50.
So I think $12.50 represents more.
Ah, that being class, how much they can raised by
stew. And that's why sometimes we just get rid of
their ah, liars to get a better sense of what
really is going on.
Um, in that class.
Okay, So how do our lives?
Affected means.
Sometimes he breaking, He brings it up.
Like this case is probably up to 20.
But if those are liars were on the left side
of the cluster, then it would probably bring the average
town. Okay, so you said out there liars pull them
mean higher or lower and nowhere.
How? Liar caused the mean lower.
Then the center of the data set on a high.
A liar who's pulls the mean higher than the center.
All right, so now it's your turn, You guys to
find the mean for the choir class and for the
stream class, make sure that you answer these and eternity