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this video was specifically requested
from a commentator of another video of
mine
the person wanted more examples of
population means and so that's exactly
what i'm going to do i'm going to just
simply go over
what a parameter is in regards to the
population mean and then go through
those examples
so we have the formula at the top it's
the summation of x
i over n equals mu
which is a parameter now a parameter
is something that is true it's not an
approximation it's not something you're
guessing at
this is what it is and that's what makes
it different from a sample mean
you're not trying to approximate this
parameter
you just have it the first example is
what is the population mean
size of the seven families in your
neighborhood so you live in a
neighborhood
say you have seven families what is the
average size of those families
it's going to be a population mean
because you just have seven families in
your neighborhood you don't have
eight nine ten or eleven you don't have
three
you just have seven families so you're
getting the totality of
everything and it's gonna be crunched
into this one parameter
not a statistic and so the family sizes
in your neighborhood
are 7 1 3 2
4 3 and 4. and so how would you go about
calculating that using the formula
this is what it looks like so you have
the mu
for the parameter the summation of x i
over capital n
you have the numbers all added up here
and then you divide by the number of
families you have which is 7.
you add it up you get 24 divided by 7
you get
3.43 as the average family size in your
neighborhood
this is a real parameter that you can
have this isn't using
thousands of bits of data you can do
this in your own
area where you live to find out you know
what is your population mean for family
sizes
you know maybe it's apartments maybe
it's something else but it's a realistic
question
that you may want to know for a variety
of reasons
you know there's real world application
and knowingness
the next is what is the population mean
weight in kilograms of the 2239 people
in the city
so it's going to go over the same
process
i don't have a list of the two thousand
two hundred thirty nine people
because frankly that i would not be able
to show all those numbers without
giving you some excel sheet and the
numbers would be meaningless to you
anyway because that would just be a data
overload
so this is how it would look like in
terms of
how you're writing it just for
simplicity's sake
so you have you calculate the mu just
like before you have summation of x
i over n but you use something
to summarize the 2239 people
usually it's going to be excel usually
it's going to be something
where you can do that it's not going to
be in by hand or on paper
and then you divide by 2239 because
that's what the
population of the city is and so i've
got this
uh this total here 170 835.7
divided by 2239 divided by the
the amount of people this number is just
the summarization of the weights of
all 2239 people that's all that it is
you're just adding them all together and
then you're dividing by the amount of
people that are in the city
and it gives you 76.3 kilograms
so that's the average weight of the
people in the city
that is not a statistic it is not
something you're approximating it is
something that is true
and that is something that if you used
other statistical methods
you may use to find out say the standard
deviation
when you're dealing with parameters it's
something that is true you're not
approximating it
it's just what it is if you found this
to be helpful please like and subscribe
if you have any questions please leave
them down in the comments below
i may make a video like this one where
i'm responding to
a commenter's request
thank you and stay nerdy my friends
