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# What is the Difference between Standard Deviations and z-scores, calculated within Excel ?

Posted on 2016-10-20
Medium Priority
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Hi

I want to know what is the exact difference between Standard Deviations and z-scores, with respect to the excel ? Do they represent the same values or what ?

Which one is easy to calculate within excel ? I have data in a column, for one year, each day data in a separate row. And I have to calculate the values which will represent the Standard Deviations and z-scores of

+4
+3
+2
+1
0
-1
-2
-3
-4

Will I get the same result in both the methods ?

Thanks
0
Question by:Wanu San
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LVL 29

Accepted Solution

Dr. Klahn earned 1600 total points
ID: 41853171
The standard deviation is a basic measure of the "scatteredness" of data and it applies to the entire data set.

The z-score is a measure of how many standard deviations away from the mean a raw datum is and it applies to individual values.

Thus the two are not the same.  The standard deviation of the data set must be computed before the z-score of each value can be determined.
1

LVL 22

Assisted Solution

crystal (strive4peace) - Microsoft MVP, Access earned 400 total points
ID: 41853178
syntax:
Z.TEST(array,x,[sigma])

sigma is optional. If omitted, the sample standard deviation is used.
1

Author Comment

ID: 41855748
Thank you Dr. Klahn and crystal.
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