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and science in this video I'd like to go

over how to calculate your q1 your q3

and your IQR the interquartile range so

let me quickly go through the steps and

then I'll work an example

step one is order the numbers from least

to greatest step two will identify the

extremes step three will find the median

of the data set then step four we will

find the q3 or the upper quartile this

is the median of the upper half of the

data and you will only use the data to

the right of the original median for

this step and then step five will do the

same thing but for q1 and then we will

calculate the IQR or the interquartile

range by subtracting the lower quartile

q1 from the upper quartile q3 and here's

our list of numbers okay and so what I

did was I went ahead and put them in the

put them in order from least least to

greatest okay so step one is identify

the extremes so the extremes are 65 and

100 okay so I can write extremes 65 and

100 okay step three is I'm gonna find

the median of the data set and I'm gonna

do that by crossing numbers out so I'm

gonna cross these out

okay and now I am left with two so when

you are left with two whenever you have

an even number because if you count I

have one two three four five six seven

eight nine ten

you just take an average of the two

numbers and that will be 80 plus 82

which is 162

and then I'll divide that by two and

that equals 81 so the median equals 81

okay now step four is I'll find q3 or

the upper quartile okay so what I will

do is I will you need the same number in

each quartile so I have one two three

four five one two three four five so I

won't write the medium eighty one there

I'll just go with the numbers that you

have so this will be Q 3 and this set

will be Q 1 okay and so now to find the

median of this and I'm gonna rewrite

these numbers so it's not as messy I

have 82 85 90 95 and 100 okay so I'm

gonna cross them off like I did before

and the median is 90 so I will label

that Q 3 equals 9

now I'm gonna rewrite Q 1 I have 65 65

70 75 80

and seventy is your q1 okay and then for

my IQR I just take let me write this

here sorry I just take Q 3 and subtract

Q 1 and that equals 20 and that is your

IQR okay now let me point one thing

point one thing out if I had a an odd

number say 65 70 75 80 and 82 and I

needed to divide it into a q1 and q3 so

the median is 75 and so what I would do

it would not be included in q3 and it

would not be included in q1 okay because

you need the same number in each so

anyway I hope that helps with q1 q3 and

your IQR thanks for watching and

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