Guass normal distribution curve (XL2000)

[milonguero]

Is someone aware of the existence of a control or utility capable of displaying the Gauss normal distribution curve (the actual graphic) based on data on a certain range?. All the formulae to get the stats is there but...I can't find the graphic part of it...
Thanks in advance.

[DaleNapier]

If you have the formula, the data, and Excel, that is all that is needed. Run your data in one column, the estimated values based on the formula in another, your y-axis in a third (if applicable), and graph it. This is so obvious, I wonder if there is a complication you have not mentioned.

[milonguero]

Well...it's a little less than obvious....the formulae available in Excel are stat variables (avg, variances and the such...). not exactly what you'd use to plot the graph where you need a y= f(x) approach. Also, the idea was to find a pre-packaged control...like a date picker or the such to incorporate to the application.

[Wassim]

<img src=/S/hello.gif border=0 alt=hello width=25 height=29> miloguero

Not understanding what exactly you are trying to do, chart, or find a formula, I have found these by simply searching the OLH and the MSKB using the string "Gauss normal distribution curve"

OK check the functions:
NORMSDIST
NORMSINV
NORMINV
NORMDIST

I also found these two MSKB articles that might be helpful:

XL: How to Create a Bell Curve Chart

HOW TO: Create a Normal Chart from a PivotTable in Excel 2000

I hope these work for you. If not post a reply with more details.

Wassim

[milonguero]

Basically what I was looking for was an ActiveX control that could take as an argument the data range of a certain worksheet. Granted, there are several ways to do it. Controls are easier to handle programmatically and I lend themselves to the kind application I am working on. Also the articles were useful....I just wondered if there was out there a pre-packaged utility.

[Wassim]

<img src=/S/hello.gif border=0 alt=hello width=25 height=29> milonguero

OK Try and search for ActiveX controls at the MS Download Center or possibly post your message in the Software Finds and Wants.

I don't know if there is such a thing, because MS-Excel does have its own charting engine, but as my idol James Bond 007 said, Never Say Never.

Best of luck

Wassim aka Mister Kiss Kiss Bang Bang

[cshenoy]

I frequently make Gaussian charts using the NORMDIST function to generate the y values for an x-y smooth line chart.

For the x values, I typically start 4 standard deviations below the mean and end at 4 standard deviations about the mean.

Generally, I specify the mean and standard deviation from data or another source, the find the beginning value and the ending value. Assuming you need approximately 200 values to get a smooth curve, I calculate the interval needed for the intermediate x values. Next calculate the height of the normal curve at each point using =Normdist(value, mean, standard devation, false). Use false for a pdf probability distribution function) and true for a cdf ( cumulative distribution function).

I've attached an example spreadsheet.

[cshenoy]

I didn't really address the question about pre-package utilities. There are a couple that I have used, but I don't think they are very good. Stat Pro is an excel add-in by Chris Albright is good on stats, but not as good on the charts.