1. 4.8:Mean, Median, Mode & Range
Measures of Central Tendency

2. Definition
Mean Means Average

3. How to Find the Mean of a Group of Numbers
Step 1 – Add all the numbers.
8, 10, 12, 18, 22, 26
= 96

4. How to Find the Mean of a Group of Numbers
Step 2 – Divide the sum by the number of addends.
8, 10, 12, 18, 22, 26
= 96
How many addends are there?

5. How to Find the Mean of a Group of Numbers
Step 2 – Divide the sum by the number of addends. 1 6 6) 96
# of addends
sum 6 3 6 3 6

6. How to Find the Mean of a Group of Numbers
The mean or average of these numbers is 16.
8, 10, 12, 18, 22, 26

7. Ex1 :What is the mean of these numbers?
7, 10, 15
10.6

8. Ex 2: What is the mean of these numbers?
2, 9, 14, 27 13

9. Definition
Median is in the Middle

10. How to Find the Median in a Group of Numbers
Step 1 – Arrange the numbers in order from least to greatest.
21, 18, 24, 19, 27
18, 19, 21, 24, 27

11. How to Find the Median in a Group of Numbers
Step 2 – Find the middle number.
21, 18, 24, 19, 27
18, 19, 21, 24, 27

12. How to Find the Median in a Group of Numbers
Step 2 – Find the middle number.
18, 19, 21, 24, 27
This is your median number.

13. How to Find the Median in a Group of Numbers
Step 3 – If there are two middle numbers, find the mean of these two numbers.
18, 19, 21, 25, 27, 28

14. How to Find the Median in a Group of Numbers
Step 3 – If there are two middle numbers, find the mean of these two numbers. 46 =
median 23 2) 46

15. Ex 4: What is the median of these numbers?
16, 10, 7
7, 10, 16 10

16. Ex 6: What is the median of these numbers?
31, 7, 2, 12, 14, 19
2, 7, 12, 14, 19, 31 13 2)
= 26 26

17. Mode is the most Popular
Definition
Mode is the most Popular

18. How to Find the Mode in a Group of Numbers
Step 1 – Arrange the numbers in order from least to greatest.
21, 18, 24, 19, 18
18, 18, 19, 21, 24

19. How to Find the Mode in a Group of Numbers
Step 2 – Find the number that is repeated the most.
21, 18, 24, 19, 18
18, 18, 19, 21, 24

20. Ex 7: number is the mode?
29, 8, 4, 8, 19
4, 8, 8, 19, 29 8

21. Ex 8: Which number is the mode?
1, 2, 2, 9, 9, 4, 9, 10
1, 2, 2, 4, 9, 9, 9, 10 9

22. What is an Outlier?
A data item that is far apart from the rest of the data items
Which will an outlier affect the most: the mean, median or mode? (Hint: Think of class test scores
Sometimes you can throw out the outlier to find a more accurate mean

23. You need a mean test score of 90 points
You need a mean test score of 90 points. So far, you have taken 5 tests: 94, 84, 90, 88, and 91. What is the minimum score you need on your next test to get an A.

24. Video

25. Copyright © 2000 by Monica Yuskaitis
Homework
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Copyright © 2000 by Monica Yuskaitis