1. Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes

2. Order the numbers and find the middle value.
Warm Up
Use the numbers to answer the questions. 146, 161, 114, 178, 150, 134, 172, 131, 128
1. What is the greatest number?
2. What is the least number?
3. How can you find the median?
178
114
Order the numbers and find the middle value.

3. Problem of the Day
Ms. Green has 6 red gloves and 10 blue gloves in a box. She closes her eyes and picks some gloves. What is the least number of gloves Ms. Green will have to pick to ensure 2 gloves of the same color? 3

4. Learn the effect of additional data and outliers.

5. Vocabulary
outlier

6. The mean, median, and mode may change when you add data to a data set.

7. Additional Example 1: Sports Application
A. Find the mean, median, and mode of the data in the table. 7 5 11
Games
2002
2001
2000
1999
1998
Year
EMS Football Games Won
mean = 7 modes = 5, 7 median = 7
B. EMS also won 13 games in 1997 and 8 games in Add this data to the data in the table and find the mean, median, and mode.
mean = 8 modes = 5, 7 median = 7
The mean increased by 1, the modes remained the same, and the median remained the same.

8. MA Basketball Games Won
Check It Out: Example 1
A. Find the mean, median, and mode of the data in the table. 11 6 4 13
Games
2002
2001
2000
1999
1998
Year
MA Basketball Games Won
mean = 8 mode = 6 median = 6
B. MA also won 15 games in 1997 and 8 games in Add this data to the data in the table and find the mean, median, and mode.
mean = 9 mode = 6 median = 8
The mean increased by 1, the mode remained the same, and the median increased by 2.

9. An outlier is a value in a set that is very different from the other values.

10. Additional Example 2: Application
Ms. Gray is 25 years old. She took a class with students who were 55, 52, 59, 61, 63, and 58 years old. Find the mean, median, and mode with and without Ms. Gray’s age.
Data with Ms. Gray’s age:
mean ≈ no mode median = 58
Data without Ms. Gray’s age:
mean = 58 no mode median = 58.5
When you add Ms. Gray’s age, the mean decreases by about 4.7, the mode stays the same, and the median decreases by The mean is the most affected by the outlier. The median t is closer to most of the students’ ages.
Ms. Grey’s age is an outlier because she is much younger than the others in the group.
Helpful Hint

11. Check It Out: Example 2
Ms. Pink is 56 years old. She volunteered to work with people who were 25, 22, 27, 24, 26, and 23 years old. Find the mean, median, and mode with and without Ms. Pink’s age.
Data with Ms. Pink’s age:
mean = 29 no mode median = 25
Data without Ms. Pink’s age:
mean = no mode median = 24.5
When you add Ms. Pink’s age, the mean increases by 4.5, the mode stays the same, and the median increases by The mean is the most affected by the outlier. The median is closer to most of the students’ ages.

12. Additional Example 3: Describing a Data Set
The Yorks are shopping for skates. They found 8 pairs of skates with the following prices:
$35, $42, $75, $40, $47, $34, $45, $40
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
Mean:
358 8 =
= 44.75 8
The mean is $44.75.
The mean is higher than most of the prices because of the $75 skates, and the mode doesn’t consider all of the data.

13. Additional Example 3 Continued
The Yorks are shopping for skates. They found 8 pairs of skates with the following prices:
$35, $42, $75, $40, $47, $34, $45, $40
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
Median:
34, 35, 40, 40, 42, 45, 47, 75
82 2 =
= 41
The median is $41.
The median price is the best description of the prices. Most of the skates cost about $41.

14. Additional Example 3 Continued
The Yorks are shopping for skates. They found 8 pairs of skates with the following prices:
$35, $42, $75, $40, $47, $34, $45, $40
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
mode:
The value $40 occurs 2 times, and is more than any other value. The mode is $40.
The mode represents only 2 of the 8 values. The mode does not describe the entire data set.

15. Check It Out: Example 3
The Oswalds are shopping for gloves. They found 8 pairs of gloves with the following prices:
$17, $15, $3, $12, $13, $16, $19, $19
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
Mean:
114 8 =
= 14.25 8
The mean is $14.25.
The mean is lower than most of the prices because of the $3 glove, so the mean does not describe the data set best.

16. Check It Out: Example 3 Continued
The Oswalds are shopping for gloves. They found 8 pairs of gloves with the following prices:
$17, $15, $3, $12, $13, $16, $19, $19
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
Median:
3, 12, 13, 15, 16, 17, 19, 19
31 2 =
= 15.5
The median is $15.50.
The median price is the best description of the prices. Most of the gloves cost about $15.50.

17. Check It Out: Example 3 Continued
The Oswalds are shopping for gloves. They found 8 pairs of gloves with the following prices:
$17, $15, $3, $12, $13, $16, $19, $19
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
mode:
The value $19 occurs 2 times, and is more than any other value. The mode is $19.
The mode represents only 2 of the 8 values. The mode does not describe the entire data set.

18. Check It Out: Example 3 Continued
The Oswalds are shopping for gloves. They found 8 pairs of gloves with the following prices:
$17, $15, $3, $12, $13, $16, $19, $19
What are the mean, median, and mode of this data set? Which statistic best describes the data set?
mean = $ mode = $19 median = $15.50
The median price is the best description of the prices. Most of the gloves cost about $15.50.
The mean is lower than most of the prices because of the $3 gloves, and the mode is higher because of the two pairs costing $19.

19. Some data sets, such as {red, blue, red}, do not contain numbers.
In this case, the only way to describe the data set is with the mode.

20. Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems

21. Lesson Quiz
At the college bookstore, your brother buys 6 textbooks at the following prices: $21, $58, $68, $125, $36, and $140.
1. Find the mean.
2. Find the median.
3. Find the mode.
4. Your brother signs up for an additional class, and the textbook costs $225. Recalculate the mean, including the extra book.
$74.67
$63
none
$96.14

22. Lesson Quiz for Student Response Systems
1. The weights of 7 members of a family are 48 kg, 52 kg, 63 kg, 75 kg, 52 kg, 64 kg, and 67 kg. Identify the median.
A. 48 kg
B. 52 kg
C. 63 kg
D. 75 kg

23. Lesson Quiz for Student Response Systems
2. The heights of seven dogs at a vet are 17 inches, 14 inches, 13 inches, 21 inches, 17 inches, 15 inches, and 22 inches. Identify the mode.
A. 17 in.
B. 16 in.
C. 15 in.
D. none

24. Lesson Quiz for Student Response Systems
3. Lopez buys 5 collectibles at the following prices: $15, $12, $15, $13 and $16. He then buys another collectible at $75. Identify the mean with and without the sixth collectible.
A. $24.33; $14.20
B. $14.20; $13.83
C. $14.20; $12.64
D. $24.33; $29.20