ASA Connect

Please can someone help me with simple program to find the 3-sigma control limits of a chart for process dispersion using  interquartile range.

Thanks

Olatunde 

Olatunde-

I would be glad to help you but need a little more info to make sure I am answering your question and providing useful guidance.

Can you provide more details on your objectives and data?  Is this a real problem with a real process or an academic/course scenario?

For example:

1.  Do you have multiple data points per sample?  What is the sample size?

2.  Is your objective to construct a control chart for the within sample variation?

3.  Why do you want to use the interquartile range?

Regards,

-Walt