Question

how do you find the quartiles of a set of data?

Answer 1

For example interquatile outer quartile etc.

Answer 2

Let's take a look at whatever learning materials you have for this statistics / data analysis course. Have you tried looking up "quartiles?" Do your online learning materials discuss examples of finding "five number summaries" of data (which include three quartiles)?

Answer 3

Do you have in front of you a data set that we could use for practice in finding the first and third quartiles and the median?

Answer 4

44, 49, 39, 43, 50, 44, 45, 49, 51

Answer 5

Please arrange this data in ascending order, and count how many data you have.

Answer 6

39, 43, 44, 44, 45, 49, 49 50, 51 theres 9 numbers

Answer 7

which of these numbers is exactly in the middle of this string of data?

Answer 8

45

Answer 9

Right. What name are you going to give to 45?

Answer 10

median

Answer 11

You're doing fine. Now, how many data points have you to the LEFT of the median?

Answer 12

4

Answer 13

Right. So, with four data points on the left, we don't have a single middle point, do we?

Answer 14

If not, then which TWO data points are right in the middle of these four?

Answer 15

43 and 44 right?

Answer 16

Yes. What is the mean (average) of 43 and 44?

Answer 17

sorry i took long had to draw it out.

Answer 18

43.5

Answer 19

Right. What name do you assign to this figure?

Answer 20

um interquartile range?

Answer 21

No, that 43.5 is your first quartile, Q1.

Answer 22

What are your four data points to the right of your median?

Answer 23

oh, they are 49,49,50,51

Answer 24

Since you have an even number (4) here, there's no midpoint / median.
Therefore, to find the 3rd quartile (Q3), you must select which two data points and find their mean?

Answer 25

49 and 50 , and the mean for that is 49.5

Answer 26

Yes. And what label would you assign to this 49.5?

Answer 27

quartile 3?

Answer 28

Yes, or "third quartile."

Which is the smallest data point in your set of 9 data points? the largest?

Answer 29

39, and 51

Answer 30

OK: very nice! Please write out these five numbers:

Minimum, Q1, Median, Q3, Maximum.

Answer 31

39, 43.5, 45, 49,5, 51?

Answer 32

Yes. Have you a proper label for these five numbers?

Answer 33

you listed them already

Answer 34

Well, yes, and well, no. These five numbers make up your "five number summary."

What does "IQR" stand for ?

Answer 35

inner quartile range

Answer 36

Right. How does one find the IQR, given Q1 and Q3?

Answer 37

subtracting

Answer 38

i got 6

Answer 39

You've subtracted 43.5 from 49.5? Great.

Any questions about finding quartiles now?

Note that the median is sometimes referred to as Q2.

Answer 40

No thanks i got it, Thankyou for your help!

Answer 41

My great pleasure. Practice on other sets of data to strengthen and set your skills. Good luck1 And thank you for the medal.

Answer 42

No problem