Confidence Interval

[arfasih]

Hello

How can I calculate Confidence Interval By MS SQL?

I have an Array of Data, and I'm looking for a method Like Confidence Interval in Excel.


Thank you very much in advance,

Regards,
Fasih

 

[MajP]

This is a pretty nebulous question. What are you exactly wanting to calculate? This could have hundreds of meanings.

Do you mean:
The confidence interval for a population mean, with a known standard deviation, and values assumed to come from a normal distribution?

 

[lespaul]

To calculate the confidence interval you will need to have 3 pieces of information alpha, sigma and n...you should have that information in your excel spreadsheet.

You will probably need to build your own function to get this in MS SQL (you may want to also post in Forum183 )

You'll first have to create an algorithm for computing the inverse normal cumulative distribution function, here's a website that shows how:

http://home.online.no/~pjacklam/notes/invnorm/

Then you'll need to use that information and develop the following formula:

NORMSINV(1 – alpha/2) * sigma / SQRT

where NORMSINV is the function you created above.

HTH

Leslie

 

[jedraw]

You can look at this MSoft site that shows how to call Excel functions from within Access.

Note: You'll have to include a reference to Excel Object Library

http://support.microsoft.com/kb/153748