Thread: Interquartile range

hello all,
please help as I'm very stuck!

I have 50 numbers.
I need to work out the interquartile range so i need the upper and lower quartiles.

which numbers do i use? all examples i find seen to be odd in total.

for the lower quartile i think I need the

50+1
-------- = 12.75th number
4

and for the upper quartile i think i need the

3(50+1)
----------- = 38.25th no.
4


how can i find this or am I going about this all wrong?
I dont understand how to get the 12.75th or 38.25th number.

Please help me! thanks a bunch. Will

Originally Posted by knottwill

hello all,
please help as I'm very stuck!

I have 50 numbers.
I need to work out the interquartile range so i need the upper and lower quartiles.

which numbers do i use? all examples i find seen to be odd in total.

for the lower quartile i think I need the

50+1
-------- = 12.75th number
4

and for the upper quartile i think i need the

3(50+1)
----------- = 38.25th no.
4


how can i find this or am I going about this all wrong?
I dont understand how to get the 12.75th or 38.25th number.

Please help me! thanks a bunch. Will

An algorithm for doing this can be found here

RonL