1. Mode
Mean
Range
Median
WHAT DO THEY ALL MEAN?

2. A number that helps describe a set of data is an AVERAGE!
Sometimes called a
MEASURE OF CENTRAL TENDANCY

3. ALL OF THESE ARE AVERAGES:
MEAN
MEDIAN
MODE
We use the word the wrong way when we ask a teacher, “What’s my average?”
What we should say is, “What’s my mean?”

4. Mean This is what we usually mean when we say “What’s my average.”
We could say, “What grade do I normally get?”

5. How is the mean of a set of numbers found?
Add all the numbers in the set together.
Divide the sum by the number of data items in the set.
The quotient is the mean of the set of numbers.
Example: 10, 18, 12 and 16
Add = 56
Divide 56 by 4
The mean is 14

6. Median Is the number that is in the middle of a set of numbers.
Half the numbers are below the median and Half the numbers are above the median

7. How is the median of a set of numbers found?
Arrange the numbers in the set in order from least to greatest.
The middle number is the median of a set of numbers.
If more than one number is in the middle of the set of numbers, the mean of those two numbers is the median of the set of numbers.

8. Your grades on five tests: 95, 87, 92, 100, and 85
Put them in order from least to greatest
85, 87, 92, 95, 100
Your median test grade is 92 – half the time you score below 92 and half the time below 92
The middle number is the median

9. Your grades on six tests: 95, 87, 92, 100, and 94
Put them in order from least to greatest
85, 87, 92, , 95, 100
The median is the mean of 92 and 94 Or
= 186
186 divided by 2 = 93
The middle is between 2 numbers

10. Mode Most of the time you get a 100
The number in a data set that occurs most often
Your grades: 95, 87, 85, 100, 100
Your mode is 100
Most of the time you get a 100

11. How do I identify the mode of a set of numbers?
Arrange the set of numbers in order from least to greatest.
The number that occurs the most often is the mode of that set of numbers.

12. You don’t have to have a mode…….
Some data sets have no mode or no number that occurs more than others
Some might have two modes

13. RANGE Asks the Question: Another way to describe data
How spread out is my data?
Another way to describe data

14. How is the range of a set of numbers identified?
Arrange the numbers in the set in order from least to greatest.
Subtract the lowest number from the highest number in the set of numbers.
The difference of the two numbers is the range of a set of numbers.

15. Back to your test Scores:
95, 87, 92, 100, and 94
Your highest score is a 100
Your lowest score is 87
Your range is 100 – 87 = 13
The range = 13

16. It’s Time To Practice! Number of pets owned by 7 students:
2, 1, 1, 4, 3, 2, 1 2
What is the mean
What is the median 2 1
What is the Mode 3
What is the Range

17. 4 ways to describe data
The Mean – what we usually think of as the average…..
The Median – The middle number in a data set…..50% of the numbers are above and 50% are below the median
The Mode – The number that occurs most often…..
The Range – the difference between the smallest and bigest number…..