Help me Please "plot bell curve on Histogram"

[Victoria Winn]

Hello!

My name is Victoria! I have to plot a bell curve on a histogram and
I do not know how!! I can only get a value when using the normal
distribution function, but I already have the data and the histogram I
have to plot a bell curve over the histogram.

If any one could help me solve this problem it would be greatly
appreciated.

I have not been using excel for a long time and I only recently
found out about the add-ins, i have a couple of books that are of no
help to me!

Thank you!!

Victoria

[Tushar Mehta]

[This followup was posted to microsoft.public.excel.charting and a
courtesy email copy was sent to Victoria Winn <vw...@sympatico.ca>.
Please use the newsgroup for further discussion.]

If I understand your question, then, for the data you have create a
histogram using Tools | Data Analysis... | Histogram

--
Regards,

Tushar Mehta
www.tushar-mehta.com
--
In <389638A7...@sympatico.ca>, Victoria Winn <vw...@sympatico.ca>
wrote

[Peter Beach]

Victoria,

One way of doing it is to construct your histogram, but have it record
percentages in each bar rather than actual frequencies. I assume you have a
data table looking something like:

90 0%
91 1%
92 1%
93 1.8%
etc.

Now calculate the mean and standard deviation of your data. Assuming you
have your data running down col a and b put the following formula in cell C1
(I assume mean is in cell B22 and Std Dev in B23):

=NORMDIST(A1+0.5,$B$22,$B$23,FALSE)

This will give cell C1 the value of the normal distribution at the point
90.5 (I add the 0.5 because your histogram is, presumably, giving count of
values >= 90 and < 91). Copy the formula down and you should see the normal
values corresponding to the mid-point of each range appearing in col C.

Now to get this into your existing histogram you could try:

Select the existing data series in the chart, then right click with the
mouse and select "Source Data" from the pop-up menu. Go to the series tab
and click on the add button and then add the data series containing A1:A20
(assuming 20 rows of data) and C1:C20. You should now have a stacked
histogram. Select the new data series, right click with the mouse, select
"Chart Type" from the pop-up menu and make the chart type a line chart. You
should now have a line graph of the standard normal distribution
superimposed on the observed data recorded in the histogram.

Or at least that's what I got <g>.

HTH

Peter Beach
Excel MVP

Victoria Winn <vw...@sympatico.ca> wrote in message
news:389638A7...@sympatico.ca...

[Chrissy R]

Peter Beach wrote
<< snip>><< snip>><< snip>>

This looks good but if you had trouble following it you could try this:

- Create the data for your normal curve (as Peter said);
- Select the three columns, labels, histogram data and the normal curve
data;
- Click the chart wizard;
- Select 'Custom Types' tab;
- Select 'Line - Column' chart;
- Click 'Finished';

Then modify this chart to display the data as you want it. This method
gives you something to start with and it is usually easier to improve others
work that to create your own.

Chrissy.