6 th grade
6 th grade

Create a BoxPlot
#107
Spiral Review #28

Shape
The shape of the data distribution determines what should be used to determine the center (balance point).
Today we will focus on the distribution of the data taking on a skewed shape.
Center
If the data distribution is skewed, the is used to determine it’s center / balance point.
Variability
We are now ready to talk about the relation of the rest of the data to its center. If the median is used as the center of the distribution of data, its variability is measured by its
________________________.
The best indicator of a typical value is the data set that has the smallest variability, or in today’s topic the smallest .
InterQuartile Range
Do not include the median ( ) when finding the lower quartile ( ) and upper quartile
( ).
When all the restaurants’ data is put together, the data appears to be skewed! Let’s take a look at the five statistical measures for each of the restaurants.

Five-Number Summary
:
Minimum (min):
Maximum (max):
Median (M):
Lower Quartile (Q1):
Upper Quartile (Q3):
Range:
IQR:
60, 70, 74, 75, 76, 76, 78, 78, 79, 82, 82, 82, 82, 83, 83, 83, 83, 83, 85.
:
Minimum (min):
Maximum (max):
Median (M):
Lower Quartile (Q1):
Upper Quartile (Q3):
Minimum (min):
Maximum (max):
Median (M):
Lower Quartile (Q1):
Upper Quartile (Q3):
Range:
IQR:
Range:
IQR:

What percent of the data is in each quartile?
What percent of the data is in the IQR?
Which of the three restaurants seems most likely to really have 82 fries in a typical bag?
Restaurant mean median IQR
A 81.5 82
B
C
78.6
80.2
82
79.5
Outlier
There is a formula that is used to distinguish whether or not a piece of data is truly an outlier!
1.5(IQR) = cushion determining boundary
Q
1
– 1.5(IQR) = lower boundary
Q
3
+ 1.5(IQR) = upper boundary
The data needs to be beyond the boundary to be considered an outlier.
For Restaurant B, is the large bag with 60 French Fries an outlier?
Create a BoxPlot
Create a boxplot for each restaurant.
Restaurant A:
Restaurant B:
Restaurant C:
Number of French Fries in a Large Bag

Name: __________________________________
Pre-Algebra
Date: ______
Exit Ticket
On the graph below, insert the following words in approximately the correct position.
Maximum Minimum IQR Median Lower Quartile (Q
1
) Upper Quartile (Q
2
)
Estimate the IQR based on the data set above.
Name: __________________________________
Pre-Algebra
Date: ______
Exit Ticket
On the graph below, insert the following words in approximately the correct position.
Maximum Minimum IQR Median Lower Quartile (Q
1
) Upper Quartile (Q
2
)
Estimate the IQR based on the data set above.

Name: _______________________________________
Pre-Algebra
Date: _____
HW #107
Lesson Summary

The shape of a distribution can be either skewed or approximately symmetrical.

If the shape is skewed, the median is used to describe the distribution’s center.

If the shape is skewed, the InterQuartile Range is used to describe the distribution’s variability.

The best indicator of a typical value for the study has the smallest variability.
The maximum speeds of selected birds and land animals are given in the tables below.
1. Find the five-number summaries for birds and land animals:
Bird Land Animals
Min:
Q1:
M:
Q3:
Max:
Min:
Q1:
M:
Q3:
Max:
2. Use the five-number summaries to make a boxplot for each of the two data sets.

Review:
3 The test scores of the students in Mr. Duffy’s class are shown on the line plot below.
Most of the students in Ms. Guzman’s class scored higher than most of the students in Mr. Duffy’s class on the same test. Which line plot could represent the test scores of the students in Ms. Guzman’s class? a. b. c. d.
4. Solve the following inequality: -4(x + 2) > 44
Graph: