Mean, Median, Mode, Range, Interquartile Range

Mean, Median, Mode, Range, IQR

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Mean, Median, Mode and Range are common ways we use statistics to describe a data set

They all tell us something different about a data group

The Range of a list of numbers is just the difference between the largest and smallest value

**To find the range, subtract the smallest value from the largest value

Example: What is the range of the following data set?:

1, 20, 3, 8, 5, 21

Range = 21-1

Range = 20

Multiple Choice

Find the range of the data.

63, 71, 65, 66, 87, 53

• 32

• 33

• 34

• 35

Multiple Choice

What is the range of miniature golf scores?

• 44 points

• 29 points

• 33 points

• 39 points

Mean is the average 

We find the mean by adding all the data points and dividing by the total number of data points

Example: What is the mean of the following data set?:

2,6,8,4,9,10

Add the data points: 2+6+8+4+9+10= 39

And divide by the number of data points: 39/6

The mean (average) is 6.5

Multiple Choice

What is the definition of the mean?

• The average

• The middle number

• The difference between the highest and lowest numbers

• The number that occurs the most

Multiple Choice

Find the mean:

28, 18, 19, 18, 17

• 20

• 18

• 11

• 19

The median is the middle number

We find the middle number but putting the data points in order

Example: What is the median of the following data set?:

21,13,14,16,18,13,13,13,14

Put the numbers in order and find the middle number:

13,13,13,13,14,14,16,18,21

The median is 14

Median continued...

What do you do if there is no "middle number" ?(even number of data points)

Find the average of the two middle numbers

Example: What is the median of the data set?

1,3,4,6,8,10

Find the average of the two middle numbers. The average of 4 and 6 is 5. Therefore, 5 is the median

Multiple Choice

Find the median:

5, 6, 3, 9, 0, 4, 1, 2, 7

• 4

• 4.1

• 5

• 4.5

Multiple Choice

When finding the median, what do you do if there are two middle numbers?

• Add them together and divide by 2

• Write them both as the answer

• Give up

• Pick one

Multiple Choice

Find the median:

3, 5, 7, 4, 3, 1

• 3 and 4

• There isn't one

• 3.5

• 3

The Mode is the number that is repeated more often than any other

Example: What is the mode of the following data set?

1,1,2,2,5,5,5,8,9

5 is repeated 3 times to it is the mode of the data set

**You can have more than one mode. For example, in the following data set is considered "bi-modal" because it has 2 modes:

1,2,3,3,4,5,5,6

The mode is 3 and 5

Multiple Choice

Can there be more than one mode?

• Yes

• No

Multiple Choice

Find the mode:

5, 0, 9, 9, 3, 0, 5, 5, 4

• 9

• 5

• 3

• 7