How To Normalize Data
- May 7, 2010
- 4,617 Views
Writer
Randall Frost
When you normalize a set of data, you map the original data range into another scale. The steps for normalizing a data set are described here.
You Will Need
- Data set minimum and maximum
- Normalize scale minimum and maximum
- Number in the data set
- Normalized value
Step 1: Identify the minimum and maximum values
Identify the smallest and largest numbers in the original data set and represent them with the variables A and B, respectively.
If you are normalizing a set of data where the smallest number is 25 and the largest number is 75, set capital A to equal 25 and capital B to equal 75.
Step 2: Identify the minimum and maximum values of the normalized scale
Identify the smallest and largest numbers in the normalized scale and represent them by the variables lowercase a and lowercase b, respectively.
If you are normalizing to the range between 1 and 10, set a will equal 1 and b will equal 10.
Step 3: Calculate normalized value
Calculate the normalized value of any number x in the original data set using the equation a plus (x minus A) times (b minus a) divided by (B minus A).
“Normalize” comes from the Latin word for a carpenter’s square.
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Comments (2)
I think an error exists. One needs to take the equation of step 3 and add A to the result; otherwise the normalization is 0-9. Try plugging in the low value and high value and you will see.
about 1 year ago by Scott_Lilienthal
Hi Scott,
Suppose you have a range of numbers from A to B, and wish to normalize it to a scale of a to b. Then any number x on the A-B scale should map to a number y given by the equation a + (x-A)(b-a)/(B-A). Let's check. If x =A, then y = a (as it is supposed to). If x = B, then y = b, again as it should.
BTW, there's a typo in the second tip; strike the word ";set.";
Thank you for writing.
about 1 year ago by Randall_Frost
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