Post on 21-Jul-2015
Cumulative Frequency
It all adds up…
Cumulative Frequency
Cumulative means totalling or gradually building up. In statistics, cumulative frequencyis found by adding up all successive frequencies in a frequency distribution table.
Cumulative Frequency
Below is a frequency distribution table that shows the hours of sleep on a school night by 98 Year 8 students (from the ABS website).
Hours of Sleep Frequency
6 10
7 7
8 22
9 31
10 21
11 4
12 2
13 1
Cumulative Frequency
10
17
39
70
91
95
97
98
Cumulative Frequency
A cumulative frequency histogram is like a frequency histogram but uses the cumulative frequency column to graph the data. It looks like steps going upwards.
An ogive is a line graph drawn on the cumulative frequency histogram. The line starts at the bottom left corner of the first column and joins the top right corner of each successive column.
Tick marks every 1cm, mark scale 2cm=10
Tick marks every 2 cm, mark scale at each tick mark: 6 - 13