Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Excel standard deviation

Posted on 2014-04-09
3
363 Views
Last Modified: 2014-04-09
Experts:

Maybe I need some more coffee this morning... I'd like to get some pointers for assessing quality of some data.   I'll try to keep it simple.

Let's say I have a mean value which ranges (usually) between 1550 and 1650 (unit is not important here).

Also, I have "uncertainty" values (calculated based on partial derivatives) which may range between +/- 6 to 8.

For sake of argument, let's now assume that I have the following data sets:

Scenario 1:
Mean value = 1600
Uncertainty value = +/- 7
Thus, min = 1593 and max 1607

Scenario 2:
Mean value = 1570
Uncertainty value = +/- 8
Thus, min = 1562 and max 1578

Scenario 3:
Mean value = 1650
Uncertainty value = +/- 8
Thus, min = 1642 and max 1658

I'd like to put these values into perspective of "quality" (i.e., comparing the three different scenarios).    Given that I have a fairly consistent range for both mean values and min/max values, the proportional quality (e.g., min/mean or max/mean) may not tell a good "story" when those values will change.

That said, given these aforementioned information, does anyone one of a good way to suggest "quality" of data where slight changes in mean/min/max ranges result in different interpretation(s)?

Ideally, I'd like to plot these data (maybe on normal curve)... I'm open to suggestions though.

I hope this makes sense... again, I'm trying to keep it simple here.

Thanks,
EEH
0
Comment
Question by:ExpExchHelp
  • 2
3 Comments
 
LVL 27

Accepted Solution

by:
aburr earned 500 total points
ID: 39988871
a lot depends on your definition of "quality"
You might try- "  uncertainty divided by mean"      ie     the percent the  uncertainty is of the mean

That will magnify and emphasize the differences in your data sets
0
 

Author Comment

by:ExpExchHelp
ID: 39988904
aburr:

Ok... maybe... current values would be: .44%. .51%, and .48%, respectively.

With respect to a Gaussian (normal) curve, I've looked into suggestion from Mr. Excel.  
https://www.youtube.com/watch?v=_PqnDYMO3lw

How would you go about graphing these values where the mean value is (on average) 200 greater than uncertainty value?

Thanks in advance,
EEH
0
 
LVL 27

Expert Comment

by:aburr
ID: 39990649
The ratio between mean value and uncertainty  makes no difference. You can plot a standard bell curve with your mean and uncertainty using the method in the video no matter what the ratio. The curve will look the same (at the appropriate magnification ) no matter what the ratio.
-
You can then sum (if you want) the deviations (or square) of your underlying data from that bell curve and identify the "quality" of the data (if you can assign any reasonable meaning to that "quality").
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

How to Win a Jar of Candy Corn: A Scientific Approach! I love mathematics. If you love mathematics also, you may enjoy this tip on how to use math to win your own jar of candy corn and to impress your friends. As I said, I love math, but I gu…
When we purchase storage, we typically are advertised storage of 500GB, 1TB, 2TB and so on. However, when you actually install it into your computer, your 500GB HDD will actually show up as 465GB. Why? It has to do with the way people and computers…
Graphs within dashboards are meant to be dynamic, representing data from a period of time that will change each time the dashboard is updated with new data. Rather than update each graph to point to a different set within a static set of data, t…
Many functions in Excel can make decisions. The most simple of these is the IF function: it returns a value depending on whether a condition you describe is true or false. Once you get the hang of using the IF function, you will find it easier to us…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question