How do i find the Inter Quartile Range of a frequency table?

Value----------------Frequency



44.3 ------ 1

44.8 ------ 1

44.9 ------ 1

45.2 ------ 1

45.3 ------ 1

45.5 ------ 1

45.7 ------ 1

45.8 ------ 1

46.2 ------ 1

46.4 ------ 2

46.5 ------ 1

46.6 ------ 1

46.7 ------ 2

46.8 ------ 1

46.9 ------ 2

47 ------- 1

47.1 ------ 4

47.3 ------ 1

47.4 ------ 1

47.6 ------ 1

48 ------ 1

48.1 ------ 2

48.2 ------ 1

How do i find the Inter Quartile Range of a frequency table?Add up all the frequencies (30) and then find a quarter (7.5) and three-quarters (22.5) of that value,



Then count down the frequencies until you find the quarter numbers (because it is 7.5 it'll be the 7th and 8th). Which are 45.7 and 45.8. You then average these out, this makes 45.75.



You then do the same for the three-quarters of the way up (22nd and 23rd). both 47.1.



You then take 45.75 from 47.1. Which gives you 1.35.



If you still don't understand it try this site:

http://www.bbc.co.uk/schools/gcsebitesiz鈥?/a>



Good luck :D