Standard Deviation Chart

[Thomas M.]

Excel 2007

Just out of curiosity, is there a way to generate a standard deviation chart
in Excel?

--Tom

 

[Jon Peltier]

You can calculate standard deviations, and you can chart numbers. What
precisely is a "standard deviation chart"?

- Jon

 

[Thomas M.]

It's been years since I came across a situation where I thought doing a
standard deviation calculation and charting the results would be the way to
go. However, I do remember one request from years back where my boss wanted
two bell-shaped curves on the same report. I was working for a medical case
management company at the time, and the x-axis was to show numerical values
for diabetes patients where the higher the number the healthier the person
(in over simplified terms). The first bell-shaped curve was to show the
range that people fell into when they first entered the diabetes management
program, and the second curve was to show the range that those same patients
fell into after being in the program for a given period of time. He wanted
the area under each curve to be entirely colored in. I was working with
Excel 97 at the time, and I just seem to remember that I could not find an
easy way to produce such a chart.

--Tom

 

[Jon Peltier]

Ah, if you had said bell curve, I would have instantly known. My colleague
Tushar Mehta has a tutorial on the topic here:

http://www.tushar-mehta.com/excel/charts/normal_distribution/

- Jon
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Jon Peltier, Peltier Technical Services, Inc.
http://PeltierTech.com/WordPress/>
Advanced Excel Conference - Training in Charting and Programming
http://peltiertech.com/Training/2009-06-ACNJ/AdvExcelConf200906ACNJ.html
_______

 

[Thomas M.]

Oh, yeah, sorry. For some reason I have always thought about that the
approach for that particular issue being one in which you calculate the mean
for the population and then break the population down into groups of +/- 1
standard deviation, +/- 2 standard deviations, etc. So I've just always
thought of it as a "standard deviation" chart. But you're right, the term
"bell curve" is probably a more readily understandable description.

I just noticed your latest reply, so I haven't yet had a chance to review in
detail the article that you linked to in the reply. However, just glancing
at the article it looks like it's what I need. I'll try to take a look at
it this weekend.

Thanks for the help.

--Tom

 

[Thomas M.]

I checked out the link that you posted. I used the first method to create a
chart with a bell curve. I then added a second data series using a
different mean and added that data series to the chart. The result was one
chart containing two bell curves, which is what I wanted.

However, I could not get the second method to work. I followed the
instructions to the letter, but when I try to enter the formulas for the X
and Y values in the data series, I get an message indicating, "The formula
you typed contains an error." I think that the article is written for Excel
2003, whereas I'm using 2007, so maybe I am not making the translation
correctly or something.

--Tom