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Edexcel IGCSE Maths 復(fù)習(xí)筆記 6.1.5 IQR & Range

Category: IGCSE課程, 國際課程, 教材筆記, 福利干貨 Date: 2022年6月29日下午12:49

Edexcel IGCSE Maths 復(fù)習(xí)筆記 6.1.5 IQR & Range

What are IQR and the range?

The three averages (mean,?median?and?mode) measure what is called?central?tendency?– they all give an indication of what is typical about the data, what lies roughly in the middle, etc.
The?range?and?inter-quartile?range?(IQR) measure how?spread?out the data is.
These can only be applied to numerical data, and both are easy to work out!

What do I need to know?

1. Range?(Hi-Lo)

This is the difference between the highest value in the data and the lowest value

Range-Demo

It measures how spread out the data is
It is simply the?HIGHEST?of all the values?TAKE AWAY?the?LOWEST?of all the values
For example, find the range of 14, 16, 18, 22

Hi = 22

Lo = 14

Range = 22 – 14 = 8

2. Inter-Quartile Range?(IQR)

This is the difference between the?upper?quartile?and the?lower?quartile
You know the median splits data into two
Well as their name suggests, quartiles split the data into four

Quartiles-Demo

IQR = UQ - LQ

9.1.5-IQR-and-Range-RN-1

For example, find the inter-quartile range of the follow data …

20, 23, 32, 35, 37, 38, 43, 45, 47, 49, 52, 56, 58, 58, 59

9.1.5-IQR-and-Range-RN-2

Exam Tip

Remember with the range that you have to do a calculation (even if it is an easy subtraction).? It is not good enough to write something like the range is 14 to 22.

Worked Example

9.1.5-IQR-and-Range-Worked-Example-1

轉(zhuǎn)載自savemyexam

Hi = 22

Lo = 14

Range = 22 – 14 = 8

2. Inter-Quartile Range?(IQR)

This is the difference between the?upper?quartile?and the?lower?quartile
You know the median splits data into two
Well as their name suggests, quartiles split the data into four

Quartiles-Demo

IQR = UQ - LQ

9.1.5-IQR-and-Range-RN-1

For example, find the inter-quartile range of the follow data …

20, 23, 32, 35, 37, 38, 43, 45, 47, 49, 52, 56, 58, 58, 59

9.1.5-IQR-and-Range-RN-2

Exam Tip

Remember with the range that you have to do a calculation (even if it is an easy subtraction).? It is not good enough to write something like the range is 14 to 22.

Worked Example

9.1.5-IQR-and-Range-Worked-Example-1

Hi = 22

Lo = 14

Range = 22 – 14 = 8

2. Inter-Quartile Range?(IQR)

This is the difference between the?upper?quartile?and the?lower?quartile
You know the median splits data into two
Well as their name suggests, quartiles split the data into four

Quartiles-Demo

IQR = UQ - LQ

9.1.5-IQR-and-Range-RN-1

For example, find the inter-quartile range of the follow data …

20, 23, 32, 35, 37, 38, 43, 45, 47, 49, 52, 56, 58, 58, 59

9.1.5-IQR-and-Range-RN-2

Exam Tip

Remember with the range that you have to do a calculation (even if it is an easy subtraction).? It is not good enough to write something like the range is 14 to 22.