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welcome to math with mr j
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in this video i'm going to cover how to
find the mean of a data set now you may
also hear the mean being referred to as
the average so that's something to keep
in mind the mean or average is a measure
of central tendency so it gives us one
number or value to represent or describe
a data set let's jump into our examples
starting with number one where we have a
data set with five numbers to find the
mean we need to add all of the numbers
in the data set and then divide by the
number of numbers so let's set this up
and we'll start with
mean
equals
and then let's add all of our numbers so
two
plus four
plus four
plus 5
plus 5
and then we're going to divide by the
number of numbers so
1 2 3
4
5 numbers so we divide by 5.
let's add first so 2 plus 4 is 6 plus 4
is 10
plus 5 is 15 plus 5 is 20. so the sum
of the numbers is 20
and then we divide by 5. so 20 divided
by 5 is going to give us our mean
20 divided by 5 is 4
so that's our mean for that data set
four is one number or value that
represents or describes that data set so
let's move on to number two where we
have double digit numbers and then we
have more numbers within our data set
number one we had smaller numbers in
value they were a little simpler to add
and then our mean worked out nicely so
to speak we got a whole number we had a
four there let's see what happens with
number two so let's set this up we have
mean
equals
and then we will add all of our numbers
so we have 58
plus 58
plus 61
plus 68
plus 72
plus 73
plus 77
plus
81
and then we'll divide by the number of
numbers in the data set so we have one
two three four five six seven eight so
we need to divide
by eight
now we can calculate the sum
of those numbers and it's going to be
548
and then we divide by 8 to get our mean
548 divided by 8 gives us a mean
of 68
and five tenths so 68 and a half is our
mean for number two so there you have it
there's how you find the mean of a data
set i hope that helped thanks so much
for watching
until next time
peace
