Cumulative Frequency

The main focus of cumulative frequency is this idea of quartile, so I will start by looking at some of the language used.

Lower QuartileUpper Quartile

Interquartile RangeQuart should make you think of a quarter or 25%

Each item is defined as follows:

Cumulative Frequency is a fancy name for a running total, but you can use it to calculate the median, the lower quartile and the upper quartile of a set of data.

Worked Example

A couple of things to note

1) Start from 0 (assuming you’re the corresponding value for 0 is 0)2) Try and draw a smooth curve

Now you can try

Worked Example

Now you can try

Worked ExampleDraw a box plot to illustrate the data from the previous worked examples

Worked Example

Now you can try

Worked Example

Now you can try