Graphing Standard Deviation

[akk]

Hi,

I was wondering what the best way to create a standard deviation graph was? I have a single row of numbers and need to make a stadard deviation graph.

I read somewhere that the analysis toolpak would be useful for this but having installed it i'm not really sure what to do next.

Many thanks,

Andrew

 

[Dougie1]

Can you not just add error bars to your graph and have these display the standard deviation ??

 

[akk]

Do you mean create a standard deviation graph with error bars?

 

[Dougie1]

I was thinking more of just graphing your data in a bar chart and then using the error bars to display the SD, but this is maybe not what you are after.

 

[akk]

No, I don't think it is. Thanks though, I need a bell curve like this diagram.

Andrew

 

[tusharm]

There's ambiguity in your first request and this one. If what you mean is that you want a bell curve with the std. dev. marked with vertical lines, create a bell curve on a XY Scatter chart. Then, add additional series, one for each vertical line of interest.

To create a bell curve see
Drawing a Normal curve
http://www.tushar-mehta.com/excel/charts/normal_distribution/index.htm

To draw a vertical line, plot 2 points in a series: (x1,0) and (x1,y1).

No, I don't think it is. Thanks though, I need a bell curve like this diagram.

Andrew

 

[Dougie1]

Ah - I think I have got you now (but maybe not !!)

I am taking it that you have a list of SD values ??

And let's remember that each SD value is a plus and a minus value

Here is what I would do :

Copy your list of values so you have the same identical values in 2 columns.

Sort one list of SDs ascending (these represent the pluses)

1
2
3
4


Sort the other list of SDs descending (these represent the minuses)

4
3
2
1


Now copy the second descending list values under your first list so you now have one list e.g.

1
2
3
4
4
3
2
1

Highlight your data list, hit F11 to automatically graph it. This will produce a bar chart of your data.

Right Click the graph anywhere, select Chart Type, select Custom Types and select Smooth Lines.

Hopefully this will graph your data as you need it.

Cheers,

D

 

[akk]

There's ambiguity in your first request and this one. If what you mean is that you want a bell curve with the std. dev. marked with vertical lines, create a bell curve on a XY Scatter chart. Then, add additional series, one for each vertical line of interest.

To create a bell curve see
Drawing a Normal curve
http://www.tushar-mehta.com/excel/charts/normal_distribution/index.htm

To draw a vertical line, plot 2 points in a series: (x1,0) and (x1,y1).

I tried this. I didn't get a full bell though, i ended up with about 3/4s and then it just stopped half way up. I was using the mean and standard deviation of the data, could that be the cause of my problem?

Andrew