Posted by Maggie on Wednesday, June 17, 2009 at 1:37pm.
The figures below show to t he nearest minute 80 students waited to be served in a canteen.
Waiting time No. of students Cum.Freq
15 4 4
610 7 11
1115 11 22
1620 18 ?
2125 22 ?
2630 10 ?
3135 5 ?
3640 3 ?
How do i find cumulative frequency??? Don't want all the answer just need to know how to find for one, and i will try to find the rest from there

Mathematics (cumulative frequency  Reiny, Wednesday, June 17, 2009 at 1:45pm
look at the last two columns
first row: no. of students =4, so current sum=4
second row: no. of students = 7, sum of students = what it was in the last row + number of students
= 4+7 = 11
third row: no. of students = 11
sum = 11+11=22
fourth row: (your first ?)
no. of students = 18
new sum = 22+18 = 40
Can you follow my steps?
now continue down for the rest of the chart.
Don't make any arithmetic errors, once you mess up, all answers after that will be wrong. 
Mathematics (cumulative frequency  sarah, Tuesday, June 4, 2013 at 5:20pm
this is the most awefull explenation of cumulative frequence...... ever!!!!!!!