1. GSE Algebra I Unit 6A Describing DATA Day 1

2. Range, Mean, Median, Mode
Essential Question: What are the measures of center and how do we use them to analyze data?

3. Range, Mean, Median, Mode
The first step to find range, mean, median, and mode is to organize your data by listing it from the smallest to largest number.

4. Tells how spread out the data is.
Range
Tells how spread out the data is.

5. Range
The range of the data set is the difference between the largest and the smallest number in the set.
To find the range, you simply subtract the smallest number from the largest number in the set.
( 1, 1, 2, 2, 2, 3, 4, 5, 5, 5, 5)
Range = 5 – 1 = 4

6. MEAN The mean is the mathematical center
The mean takes all numbers into consideration (use all of data to calculate the mean)
The mean is affected by “extreme” data

7. The mean of the data set is its average.
To find the mean, you add up all the numbers
and divide the answer by how many numbers
you have.
( 1, 1, 2, 2, 2, 3, 4, 5, 5, 5, 5)
Mean = 3.18

8. Mean and Extreme data
Imagine that 4 houses in rural western NC are worth the following:
$27,000; $38,000; $42,000; $44,000.
Let’s find the mean cost of these houses.

9. Mean and Extreme Data
One day Oprah Winfrey flies over and decides to build a house on top of the mountain because of its scenic beauty. She builds a mansion worth $32,000,000.
Before she built, the mean cost of a house on the mountain was $37,750.
After Oprah Winfrey builds her dream house, the mean has shot up to $6,430,200!

10. Median
The median is the number which is in the exact middle of the data set.
***YOUR DATA MUST BE ORDERED***
( 1, 1, 2, 2, 2, 3, 4, 5, 5, 5, 5)
Median = 3
Note: When your set of numbers is even you take the 2 middle numbers, add them, and divide by 2.

11. Mode The mode is the number that appears the most often.
( 1, 1, 2, 2, 2, 3, 4, 5, 5, 5, 5)
Mode = 5
If no numbers are repeated, there is no mode.
If more two numbers appear the most often there are two modes.

12. Range, Mean, Median, Mode
Example 1. Two dice were thrown 10 times and their scores were added together and recorded. Find the range, mean, median, and mode for this data.
7, 5, 2, 7, 6, 12, 10, 4, 8, 9

13. Range, Mean, Median, Mode
Example 2. Nine people took a vocabulary test. Their scores (out of 10) are recorded below. Find the range, mean, median, and mode for the test.
2, 9, 3, 7, 4, 8, 6, 10, 4