1. Mean, Median, Mode, and Range
LESSON 1-10
Problem of the Day
1. Vocabulary Review When you simplify ÷ 3,
which operation should you use first?
Find the value of each expression.
2. (7 + 19) ÷ 2 3.
4. –9 + 4 • 2 –1
–14 + 6 2
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2. Mean, Median, Mode, and Range
LESSON 1-10
Check Skills You’ll Need
Solutions
1. division (7 + 19) ÷ 2 = 26 ÷ 2 = 13
–9 + 4 • 2 –1 = –9 + 8 –1 = –2
–14 + 6 2 –8 2
= –4 =
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3. Lesson 1-10 Mean, Median, Mode, and Range
These are all ways that we can draw conclusions from data.
Mean: average of all data items
 get the sum of the data, then divide by the number of items

4. Mean, Median, Mode, and Range
LESSON 1-10
Additional Examples
Find the mean of 502, 477, 593, 481, 735, and 614. 6
Divide the sum by the number of terms.
Simplify.
3,402 6
= 567
Quick Check
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5. Lesson 1-10 Mean, Median, Mode, and Range
Outlier: a data item that is very different from the other data items (much higher or lower)
Outliers can result in a misleading mean
Example:
15, 12, 14, 17, 13, 24, 12, 15
What is the outlier?

6. Lesson 1-10 Mean, Median, Mode, and Range
Median: the middle value in the data set
You MUST arrange the data in numerical order first
With an even number of data items, get the mean of the two middle values

7. Mean, Median, Mode, and Range
LESSON 1-10
Additional Examples
Find the median of the data in the chart.
18 Responses to “How many pets do you have?”
First write the data in order from least to greatest.
The two middle values are 1 and 2.
Find the mean of the two middle values.
1 + 2 2
= 1.5
The median is 1.5.
Quick Check
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8. Lesson 1-10 Mean, Median, Mode, and Range
Mode: the item that occurs most frequently
You can have more than one mode. (When?)
Can you have no mode for a data set? (When?)

9. Mean, Median, Mode, and Range
LESSON 1-10
Additional Examples
Find the mode of the data in the chart.
18 Responses to “How many pets do you have?”
Make a table to organize the data.
0 pet pet pets pets pets 8 pets
There are two modes, 0 and 2.
Quick Check
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10. Lesson 1-10 Mean, Median, Mode, and Range
Range: the difference between the greatest and least data items
Shows how spread out the data is

11. Mean, Median, Mode, and Range
LESSON 1-10
Additional Examples
Temperatures one day in January ranged from – 7°F to
11°F. What was the temperature range?
11 – (–7) = Add the opposite of –7, which is 7.
= 18 Simplify.
The temperature range was 18°F.
Quick Check
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12. Mean, Median, Mode, and Range
LESSON 1-10
Lesson Quiz
Find the mean, median, mode, and range of each set of data.
1. 25   21  27   20
2. –8  –4  2  10  –10
3. 7.5  3.6    3.6 
mean, 24; median, 25; mode, 27; range, 7
mean, –2; median, –4; mode, no mode; range, 20
mean, 9.1; median, 7.5; mode, 3.6 and 15.4; range, 11.8
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13. Lesson 1-10 Mean, Median, Mode, and Range
Homework:
Activity Lab 1-10
Lesson 1-10, p. 55 #s 1-8 all; evens; 25, 33