The mean is just the ordinary average that you
learned how to find in lower grades in school.
"Median" sound like "middle"
"Mode" sounds like "most".
To find the mean:
1. Count the numbers.
2. Add the numbers.
3. Divide the result of 2 by the result of 1.
Example:
Find the mean of the numbers 3.7, 5.6, 2.4, 6.9
1. We count them, and find there are 4 numbers.
2. We add them, 3.7 + 5.6 + 2.4 + 6.9, and get 18.6
3. We divide 18.6 by 4 and get 4.65.
So 4.65 is the mean.
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To find the median:
1. Arrange the numbers in order smallest to largest, it doesn't
matter which.
2. Count the numbers
3. If there are an ODD number of numbers, the median is the ONE middle
number.
4. If there are an EVEN number of numbers, the median is the MEAN of
the TWO middle numbers.
number.
Example 1:
Find the median of the numbers:
47, 39, 83, 76, 89, 7, 19
1. We arrange the numbers in order smallest to largest:
7, 19, 39, 47, 76, 83, 89
2. We count the numbers, and get 7.
3. 7 is an odd number so, the median is the number
right in the middle of the ordered list in step 1,
which is 47.
Example 2:
Find the median of these numbers:
15.3, 18.7, 29.4, 38.4, 18.8, 28.3
1. We arrange the numbers in order largest to smallest:
38.4, 29.4, 28.3, 18.8, 18.7, 15.3
2. We count the numbers, and get 6.
3. 6 is an even number, so the median is the mean of
the middle two numbers 28.3 and 18.8.
So we count those two middle numbers and get 2, of course
We add them, 28.3 + 18.8 and get 47.1.
We divide 47.1 by 2 and get 23.55.
So the median is 23.55.
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To find the mode:
If all the numbers are different, then there is no mode.
If any of the numbers are the same, choose the ones that occur
the MOST number of times. If there is a tie between two numbers
then there are TWO modes, and the data is said to be bimodal.
Example 1:
Find the mode of these numbers:
4,7,9,2,4,7,7,2,6
The 7 occurs 3 times which is more than any of the others,
so the mode is 7.
Example 2:
Find the mode of these numbers:
15, 18, 23, 17, 9, 68, 19
All the numbers are different, so there is no mode.
Example 3:
Find the mode of these numbers:
6, 7, 8, 7, 6, 8, 8, 2, 7
There are two modes, 7 and 8. So
this set of numbers is said to be "bimodal".
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To find the range.
1. Locate the largest and smallest numbers.
2. Subtract the smallest number from the largest number.
Example:
Find the range of the numbers:
47, 39, 83, 76, 89, 7, 19
1. The largest number is 89 and the smallest is 7.
2. We subtract 89 - 7 and get 82.
So the range is 82.
Edwin