A

6 years ago

Hi thank you so much! Is it possible for you to help me with the upper and lower quartile part in the first part?

Andrea

6 years ago

sure thing, just give me a few minutes

Andrea

6 years ago

The upper and lower quartiles are basically the medians of the upper and lower halves that I mentioned in the second part respectively. So your lower quartile is 1, upper quartile is 24

A

6 years ago

But isn't the median of the lower half
(1+0) ÷ 2 = 1/2
And the median of upper half
(24+27) ÷ 2 = 25.5

Andrea

6 years ago

Unless your halves have even no. of data, you dont have to add the middle 2 and divide it by 2. That formula is only for even numbered data. For odd no. of data, you can just take the middle number as it is.

E.g

1, 2, 3, 4, 5

Median = 3,

LQ = (1+2) ÷ 2
UQ = (4+5) ÷ 2


1, 2, 3, 4, 5, 6

Median = (3+4) ÷ 2

LQ = 2
UQ = 5

A

6 years ago

But don't both the lower and upper halves have 4 numbers each?
Eg. Lower half
0,0,1,6
Upper half
9,24,27,29

A

6 years ago

Okay thank you so much!

Andrea

6 years ago

You can use this formula for finding your quartiles.

n = total no. of data
LQ = (n÷4)th number in the arranged sequence
UQ = (3n÷4)th number in the arranged sequence

If the number has decimals, e.g 2.5, add the 2nd and 3rd number and divide it by 2. If it's 7.5, add the 7th and 8th number and divide it by 2.