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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