IGCSE MATHS HELP NEEDED!!!!

[Wahaj]

dear friends i am wahaj from peshawar pakistan........... i wanna know how to find cumulative frequency..???? plz i need quick help......

 

[larina]

e.g. there are 100 ppl in a restaurant........
range frequency cumulative frequency
0<x<5 10 10
5<x<10 13 23(we add 13 and 10)
10<x<20 39 62(we add 39 and 23)
20<x<45 22 84(we add 22 and 62)
45<x<50 16 100(this is the total number of ppl in the restaurent)


to make graph-----------we plot points (5,10), (10,23), (20,62), (45,84), and (50,100)
on x-axis-----range and on y-axis-----cumulative freq.


to get lower quartile------1/4 x 100
to get upper quartile-----3/4 x 100
to gt inter-quartile-------upper quartile - lower quartile
to get median-------------1/2 x 100

 

[Wahaj]

thanx...