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Lesson 2-4 Pages 69-72. Mean, Median, and Mode. Lesson Check 2-3. What you will learn!. How to find the mean, median, and mode of a set of data. Vocabulary. What you really need to know!. The mean is the sum of the data divided by the number of data items. - PowerPoint PPT Presentation
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Lesson 2-4 Pages 69-72
Mean, Median, and Mode
Lesson Check 2-3
What you will learn!
How to find the mean, median, and mode of a
set of data.
Measures of central tendencyMeasures of central tendency
MeanMean
ModeMode
MedianMedian
What you really need to know!
•The mean is the sum of the data divided by the number of data items.
•The median is the middle number of the ordered data, or the mean of the middle two numbers.
What you really need to know!
•The mode is the number (or numbers) that occur most often.
•The mean, median, and mode are each measures of central tendency.
Find the mean, median, and mode for each set of data!
1, 5, 9, 1, 2, 6, 8, 2
Mean = 4.25Median = 3.5Mode = 1 and 2
Find the mean, median, and mode for each set of data!
82, 79, 93, 91, 95, 95, 81
Mean = 88Median = 91Mode = 95
The line plot shows the number of children of U. S. presidents. Would the mean, median, or mode best represent the number of children?
Example 2:
0 1 2 3 4 5 6 7 8 9 10
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xxxx
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x x
There are 46 numbers. Add them together and divide the sum by 46.
7
5
11
4
6 6
32
1 1
0 1 2 3 4 5 6 7 8 9 10
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x x
143 ÷ 46 3.1 (mean)
0
5
22
12
24 30
1814
8 10
0 1 2 3 4 5 6 7 8 9 10
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xxxx
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x x
Since there are 46 numbers, the middle would be the 23rd number from the each end of the list. That would be a 2 and a 3. Take the mean of these two numbers to get the median.
0 1 2 3 4 5 6 7 8 9 10
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5 ÷ 2 = 2.5 (median)
0 1 2 3 4 5 6 7 8 9 10
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x x
Median of 2.5 best represents
the data!
Mean = 3.1
Median = 2.5
Mode = 27
5
11
4
6 6
32
1 1
Extra:
When the numbers are all in the same neighborhood, the MEAN is the way to go! If there is one number out of the neighborhood, then the MEDIAN is the choice!
Page 71
Guided Practice
#’s 4-9
Pages 69-71 with someone at home
and study examples!
Read:
Homework: Page 72
#’s 10-16
#’s 20-27
Lesson Check 2-4
Page
568
Lesson 2-4
Lesson Check 2-4
Mid-Chapter Practice Test
Page
74
#’s 1-15
1. The number of pieces of data that fall within given intervals.
2. Example: Predicting profit earned by a company for the next year.
3. The greatest and least values, clusters of data, gaps in data, how the data is spread out, the range, and the mode (the most often number).
4. Sum of data divided by the number of terms in the data set.
Example 1:The table below shows the number of species of animals found at 30 major zoos across the U.S. Find the mean.
Number of Species in Major U.S. ZoosNumber of Species in Major U.S. Zoos
300300 400400 283283 400400 175175
617617 700700 700700 715715 280280
800800 290290 350350 133133 400400
195195 347347 488488 435435 640640
232232 350350 300300 300300 400400
705705 400400 800800 300300 659659
There are 30 numbers. Add them together and divide the sum by 30.
13,094
436.46÷ 30
Calculator
Example 2:
The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data.
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 66 44 33 00
1010 66 44 22 33
1111 22 33 44 22
11 11 00 22 22
11 00 00 00 00
There are 25 numbers. Add them together and divide the sum by 25.
79 = 3.16÷ 25
Example 2:
The table below shows the number of gold medals won by each country participating in the 2002 Winter Olympic games. Find the mean, median, and mode of the data.
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 66 44 33 00
1010 66 44 22 33
1111 22 33 44 22
11 11 00 22 22
11 00 00 00 00
0 0 0 0 0 0 1 1 1 2 2 2 2 2 3 3 3 4 4 4 6 6 10
11
12
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 44 33 22 00
1111 44 22 11 00
1010 44 22 11 00
66 33 22 11 00
66 33 22 00 00
Order the numbers from greatest to least. Find the number or numbers in the middle of the list.
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 44 33 22 00
1111 44 22 11 00
1010 44 22 11 00
66 33 22 11 00
66 33 22 00 00
The median for this data is 2.
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 44 33 22 00
1111 44 22 11 00
1010 44 22 11 00
66 33 22 11 00
66 33 22 00 00
The mode is the number or numbers that occur most often.The mode for this data is 0.
2002 Winter Olympics: Gold Medals Won2002 Winter Olympics: Gold Medals Won
1212 44 33 22 00
1111 44 22 11 00
1010 44 22 11 00
66 33 22 11 00
66 33 22 00 00
