1. Mean, Median, and Mode

2. Mean The mean of a set of data is the average. Add up all of the data.
Divide the sum by the number of data items you have.

3. Example: Find the mean.
4, 16, 20, 40
First, add = 80
There are 4 items. Divide the sum (80) by 4.
The mean is 20.

4. Find your answer before the next slide!
An electronics store sells CD players at the following prices: $350, $275, $500, $325, $100, $375, and $300. What is the mean price?
Find your answer before the next slide!

5. The mean or average price of a CD player is $317.86.
$350 + $275 + $500 + $325 + $100 +$375 + $300 =
$2225
$2225 / 7 = $317.86
The mean or average price of a CD player is $

6. Median
The median is the data point that is in the middle when the data is listed in order.
If there are two numbers in the middle (an even number of items), then find the mean of the two middle numbers.

7. 12, 15, 11, 11, 7, 13
First, arrange the data in numerical order.
7, 11, 11, 12, 13, 15
Then find the number in the middle or the average of the two numbers in the middle.
= / 2 = 11.5
The median is 11.5

8. Examples: Find the median.
13, 16, 17, 19, 25
17 is the median.
3, 5, 6, 9
Here, the 5 and 6 are both in the middle = divided by 2 = The median is 5.5.

9. Find your answer before the next slide!
An electronics store sells CD players at the following prices: $350, $275, $500, $325, $100, $375, and $300.
What is the median price?
Find your answer before the next slide!

10. $100, $275, $300, $325, $350, $375, $500 The median price is $325.
First place the prices in numerical order.
$100, $275, $300, $325, $350, $375, $500
The price in the middle is the median price.
The median price is $325.

11. Mode The mode is the data item that appears the most.
If all data items appear the same number of times, then there is no mode.

12. Mode The mode is the data item that appears the most.
If all data items appear the same number of times, then there is no mode.

13. Example: Find the mode.
5, 4, 6, 11, 5, 7, 10, 5
The mode is 5.

14. Sometimes a set of data will have more than one mode.
For example, in the following set both the numbers 5 and 7 appear twice.
2, 9, 5, 7, 8, 6, 4, 7, 5
5 and 7 are both the mode and this set is said to be bimodal.

15. The range of a set of data is the difference between the largest and the smallest number in the set.
For example, consider the following set:
40, 30, 43, 48, 26, 50, 55, 40, 34, 42, 47, 50
To find the range you would take the largest number, 50, and subtract the smallest number, 26.
55 – 26 = 29
The range is 29!

16. Example: Find the range.
5, 4, 6, 11, 5, 7, 10, 5
The range is 7.

17. Example: Find the range.
80, 92, 78, 95, 87, 72
The range is 23.

18. Mean Median Mode Range The average of the numbers
The number in the middle
Mode
The number that occurs the most
Range
The difference between the highest and lowest numbers

19. Homework Time