Mean median mode_range

Mean, Median, Mode are all types of average. An

average summarises groups of data.

Mean – The average of a group of numbers.

2, 5, 2, 1, 5Mean = (2+5+2+1+5)/5 =3

Mean is found by evening out the numbers

2, 5, 2, 1, 5

Mean is found by evening out the numbers

mean = 3

Exercises: Find the mean of the following data:

1) 8, 10, 12, 18, 22, 26

2) 7, 10, 16

3) 2, 9, 14, 27

4)1, 2, 7, 11, 19

Average often means the ‘mean’

Mean = total of the numbers divided by how many numbers.

Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6

Add up the numbers:

3 + 5 + 5 + 6 + 4 + 3 + 2 + 1 + 5 + 6 = 40

Divide by how many numbers:

40 ÷ 10 = 4

The class mean shoe size is 4

Definition

Median

is in the

Middle

Median – The middle number in a set of ordered numbers.

1, 3, 7, 10, 13

Median = 7

16, 10, 7

Median=10

Solution:7, 10 , 16

29, 8, 4, 11, 19

Median=11

Sol:4,8, 11, 19, 29

Note : If there are two middle numbers, find the median of these two numbers.

18, 19, 21, 25, 27, 28

232

2521

median

31, 7, 2, 12, 14, 19

2, 7, 12, 14, 19, 31Median=12 + 14 = 26

132

26

1) 53, 5, 81, 67, 25, 78

2) 3,5,4,6,10,5,6,9,23) 5,2,3,6,4,4,3,54)16,7,2,6,4,1,7,1,1,1,3,2,11,1,

5,1,4,12

Median is the middle value

Put the numbers in order

Choose the number in the middle of the list.

If there are 2 numbers in the middle then it is halfway between them.

Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6

Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6

The class median shoe size is 4.5

Mode

is the most

Popular number

Mode – The number that appears most frequently in a set of numbers.

1, 1, 3, 7, 10, 13

Mode = 1

Step 1 – Arrange the numbers in order from least to greatest.

21, 18, 24, 19, 18

29, 8, 4, 8, 19

Mode=8

Sol: 4, 8, 8, 19, 29

1, 2, 2, 9, 9, 4, 9, 10

Mode=9

1, 2, 2, 4, 9, 9, 9, 10

22, 21, 27, 31, 21, 32

Mode=21

21, 21, 22, 27, 31, 32

Mode is the most common number

Put the numbers in order

Choose the number that appears the most frequently.

Sometimes there may be more than one mode.

Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6,6

Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6, 6

The class modal shoe size is 5,6.

Step 2 – Find the number that is repeated the most.

18, 18, 19, 15, 15, 21,12,16,17, 24,18, 19, 19

Mode=18, 19

1) 53, 5, 81, 67, 25, 78

2) 3,5,4,6,10,5,6,9,23) 5,2,3,6,4,4,3,54)16,7,2,6,4,1,7,1,1,1,3,2,11,1,

5,1,4,12

Range

is the distance

Between

Range – The difference between the greatest and the least value in a set of numbers.

1, 1, 3, 7, 10, 13Range = 13-1=12

Range is how far from biggest to smallest.

Put the numbers in order

Take the smallest number from the largest.

Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6

Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6

Subtract smallest from largest: 6 – 1 = 5

Range: 5

Step 1 – Arrange the numbers in order from least to greatest.

21, 18, 24, 19, 27

Step 2 – Find the lowest and highest numbers.

18, 19, 21, 24, 27

Step 3 – Find the difference between these

two numbers.

27 – 18 = 9The range is 9

29, 8, 4, 8, 19

Range=29 – 4 = 25

4, 8, 8, 19, 29

22, 21, 27, 31, 21, 32

32 – 21 = 11

21, 21, 22, 27, 31, 32

31, 8, 3, 11, 19

31 – 3 = 28

Sol:3, 8, 11,19, 31

23, 7, 9, 41, 19

41 – 7 = 34

7, 9, 23, 19, 41