Plotting a normal distribution
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 This topic has 9 replies, 9 voices, and was last updated 15 years, 6 months ago by Theo.

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November 20, 2006 at 8:55 am #45286
I’m trying to generate a normal plot of a group of excel values. I used the normdist function to do this. However, I get values over 1 when I do this. any tips on where I am going wrong?
0November 20, 2006 at 9:19 am #147550Try Googling “normal probability plots in excel”
0November 20, 2006 at 9:45 am #147552Google doesn’t answer my question. Is there something specific I am making a mistake with?
I have a list of values for which I want to plot a normal curve with excel. I calculated the mean and stdev for the set and then used normdist to get the p value to plot. I get values over 1 which is obviously not right.0November 20, 2006 at 12:04 pm #147556Theres no function that will draw a normal probability plot in excel.
0November 20, 2006 at 1:13 pm #147557
Robert ButlerParticipant@rbutler Include @rbutler in your post and this person will
be notified via email.I don’t use Excel for my statistics but based on a quick read of the help section for the NORMDIST function it appears the function will generate random numbers from a normal distribution with mean 0 and standard deviation = 1. If this is in fact what it is doing then you should get values greater than 1 and less than 1.
0November 20, 2006 at 8:04 pm #147603I too found no canned function, so I made a spreadsheet that accepts values, plots the histogram, provides statistics, and then overlays the normal curve shape over the histogram of plotted points. It is just part of a worksheet I use to generate SPC charts. It is not 100% automated, but it beats nothing.
Contact me offline, at [email protected] if you want to followup.
Eugene0November 20, 2006 at 8:22 pm #147608True there is no canned way to plot a normality plot in Excel – unless you purchase one of the many programs that do this.
Here’s a way to do it though:
Assumptions: raw data are in column A and you have n data values.
1) Use the RANK function in column B to rank the raw data (use the help to see how to do this)
2) Use this expression –> ((column B.5)/n) (this is column C)
3) Use the NORMINV function with column C as the probaility. (this will be column D)
4) Create a scatter plot with column A as the xaxis and column D as the yaxis.
Try that and see if that meets your needs.0November 20, 2006 at 9:39 pm #147624Siegler:Send me a note at 6SigmaGuru(at)gmail(dot)com and I’ll send you an Excel sheet for the AndersonDarling test and normal probability plot.Cheers, BTDT
0December 3, 2006 at 8:43 am #148346
VidyadharMember@Vidyadhar Include @Vidyadhar in your post and this person will
be notified via email.Dear Friend,
There is many more to explore in excel.
Please try the following path & see whether it satisfy your need or not.
1. Select Tools manu > AddIns.
2. One dialog box will appear with many option. Select “Analysis Toolpak”If analysis toolpak is not loaded in your system then ask administator to installed full version of MSOffice.
3. Again goto “Tools Menu” > select “Data Analysis” option.
4. One dialog box will appear with many option. Select “Histogram” to plot histogram & ND curve for your data.
5. Just follow the instruction appear on the Screen.
Rgds,
Vidyadhar.0December 3, 2006 at 8:44 am #148347Why ??????
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