Normal Distribution?

A

Anthony Slater

I have data consisting of 6000 numbers such as: -

1.78
4.56
2.26
8.37
8.62
4.98
0.00
1.78

The average of my data is 3.26

How do I go about plotting the distribution of the data on a chart?

ie 120 number 4.56's, 50 number 2.26's, 600 number 8.37's


Any ideas?

TIA
 
J

Jerry W. Lewis

What you are wanting is not clear.

Some possibilities include
- In a separate locatation list the unique values in one column and in a
second column use COUNTIF() to determine that there are 120 4.56's etc.
then the second column (y) vs. the first (x) as an "XY (Scatter)" chart
- Use the Analysis ToolPak to plot a histogram of the data
- Calculate the STDEV() of the data and plot NORMDIST(x,Ave,SD,FALSE)
vs. a column of hypothetical x values spanning the range

Also, if this data is supposed to follow the normal distribution, then
the sample data should be roughly symmetrical around and peaked at the
average. The three reported values (50x2.26, 120x4.56, 600x8.37) do not
sound very consistent with normality (what does the rest of the data set
look like?)

Jerry
 
M

Michael R Middleton

Anthony -

To obtain a frequency distribution and column chart, you could use Excel's
Histogram tool. Your data may or may not follow the shape of a normal curve.

For a slightly better histogram, try my free add-in from the "Better
Histogram" page at www.treeplan.com.

- Mike www.mikemiddleton.com

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