Transcript Lesson 8-2 PowerPoint

(over Lesson 8-1)
Which choice shows a line plot
for the set of data?
A.
B.
C.
D.
0%
0%
A
B
1.
2.
3.
4.
0%
C
A
B
C
D
0%
D
Main Idea and Vocabulary
Key Concept: Mean
Example 1: Find the Mean
Key Concept: Median and Mode
Example 2: Find the Mean, Median, and Mode
Example 3: Test Example
Concept Summary: Mean, Median, and Mode
Example 4: Choose Mean, Median, or Mode
• Describe a set of data using mean, median,
mode, and range (2.6.8A) (M7.E.2.1.1)
• measures of central tendency-mean,
median, mode, range.
• Mean - average
• Median – middle number (in order from least to
greatest
• Mode – number that occurs the most.
Find the Mean
ANIMALS The table below shows the number of
species of animals found at 30 major zoos across the
United States. Find the mean.
Source: The World Almanac
Find the Mean
sum of data
number of data items
Add.
= 436.4666 ...
Divide.
Answer: The mean number of species of animals is
436.47.
SLEEP The table below shows the results of a survey
of 15 middle school students concerning the number
of hours of sleep they typically get each night. Find
the mean.
A. 4 hr
B. 7.13 hr
1.
2.
3.
4.
C. 7.5 hr
0%
D
0%
C
A
0%
B
0%
D. 8.25 hr
A
B
C
D
Find the Mean, Median, and Mode
OLYMPICS The table below shows the number of
gold medals won by each country participating in the
2006 Winter Olympic games. Find the mean, median,
and mode of the data.
Find the Mean, Median, and Mode
mode:
number appearing most often, or 0
Answer: mean: 3.23; median: 2; mode: 0
PETS The table below shows the number of pets
students in an art class at Green Hills Middle School
have at home. Find the mean, median, and mode of
the data.
A. mean: 0.78; median: 1.5;
mode: 0
B. mean: 1.44; median: 1.5;
mode: 5
1.
2.
3.
4.
C. mean: 1.44; median: 1;
mode: 0
0%
D
0%
C
0%
B
0%
A
D. mean: 0.78; median: 1;
mode: 0
A
B
C
D
The average weight in pounds of several breeds of
dogs is listed below.
15, 45, 26, 55, 15, 30
If the average weight of the Golden Retriever, 70, is
added to this list, which of the following statements
would be true?
A The mode would increase.
B The median would decrease.
C The median would increase.
D The mean would decrease.
Read the Item
You are asked to identify which statement would be true if
the data value 70 was added to the data set.
Solve the Item
Use number sense to eliminate possibilities.
The mode, 15, will remain unchanged since the new
data value occurs only once. So, eliminate choice A.
Since the new data value is greater than each value in
the data set, neither the mean nor the median will
decrease. So, eliminate choices B and D.
Answer: So, the answer is C.
If the average weight of a Chihuahua is added to the
list in Example 3, which of the following statements
would be true?
A. The mean would decrease.
B. The mode would decrease.
0%
D
A
B
0%
C
D
C
D. The mean would increase.
A
0%
1.
2.0%
3.
4.
B
C. The median would stay the same.
Choose Mean, Median, or Mode
FIRST FAMILIES The line plot shows the number of
children of United States presidents. Would the
mean, median, or mode best represent the number
of children?
Choose Mean, Median, or Mode
mode: 2
Answer: The mean, median, and mode are close, with
values of 3.6, 3, and 2, respectively. Any of the
three could be used to represent the data.
SIBLINGS The line plot below shows the number of
siblings of each student in a particular classroom.
Would the mean, median, or mode best represent the
number of siblings?
A. mean
B. median
1.
2.
3.
4.
C. mode
0%
0%
D
0%
C
A
0%
B
D. any of the
three
A
B
C
D
REVIEW
1. The sizes of the bicycles owned by the students in Ms.
Garcia’s class are as follows: 20, 24, 20, 26, 24, 24, 24, 26, 24,
29, 26, 24. What are the mean, median, and mode of the data?
Mean = 24.25, median = 24, mode = 24
2. The points scored in each game by Darby Middle School’s
football team for 9 games are 21, 35, 14, 17, 28, 14, 7, 21, and
14. Find the mean, median, and mode.
Mean = 19, median = 17, mode = 14
3. Each team had the following numbers of wins: Eagles – 10,
Hawks – 8, Zipps – 9, and Falcons – 11. Find the mean,
median, and mode.
Mean = 9.5, median = 9.5, mode = none
End of the Lesson
Five-Minute Check (over Lesson 8–1)
Image Bank
Math Tools
Line Plots