1. Describing Distributions
SWBAT analyze data by looking at the distribution.
SWBAT recognize that a measure of center for a data set summarizes all of the values with a single number, while a measure of variation describes how its values vary with a single number.

2. Do Now
1. John has a collection of toy cars. He has 2 red cars, 4 blue cars, 4 black cars, and 6 yellow cars. What is the ratio of red cars to yellow cars?
1:2 B) 1:3 C) 1:5 D) 1:6
2. Patrick washes 21 cars per day. He is paid at a rate of $7.50 for every 3 cars he washes. How much is Patrick paid for each car he washes?
3. Kristin can type 160 words in 4 minutes. How many words per minute can Kristin type?
A) 12 B) 40 C) D) 640
4. What is the GCF of 12 and 24?

3. Measures of Center
The measure of center gives a numerical value (a number) to represent the center of the data.
Midpoint or Median: The midpoint of an ordered list, also known as the median, is a measure of center. It is like a balancing point.
To find median: Order all numbers in data set from LEAST to GREATEST. Identify the number that is exactly in the middle.
Ex: 2, 2, 3, 5, 7, 9, 15, 20, 22 The median would be 7.
For median, 50% of the data is greater than the median and 50% of the data is less than the median.
Mean: Mean is the average.
To calculate mean, add all of the numbers together, then divide by how many numbers there are.

4. Measures of Variability
We can describe a data set by the variability or spread of the values.
Range: The distance between the lowest and highest values in a data set.

5. Mode The mode is the number that occurs the most in a set of data.
Ex: 3, 4, 3, 9, 2, 5
The mode is 3

6. Example of Range Example: Data Set = 2, 5, 9, 3, 5, 4, 7
Reordered = 2, 3, 4, 5, 5, 7, 9
Range = ( ) = 7

7. Example of Mean Example : Data Set = 2, 5, 9, 3, 5, 4, 7
Number of Elements in Data Set = 7
Mean = ( ) / 7 = 5

8. Practicing A family has 5 children ages 2, 7,10,4, 7.
Find the range, mean, median, and mode of their ages.
Step 1: Write the ages in order: 2, 4, 7, 7, 10
Range: 10 – 2 = 8
Mean: = 30/5=6
Median: 7
Mode:7

9. Practice
Jayden has 10 grades in his math class so far. They are 98, 87, 100, 84, 97, 98, 100, 90, 92, 80.
Find the range, mean, mode, median.
Step 1: 80, 84, 87, 90, 92, 97, 98, 98, 100, 100
Range: 100 – 80 = 20
Mean: 926 / 10 = 92.6
Mode: 98 and 100
Median: = 189/2 = 94.5