NORMINV() - explain the formula?

**domgilberto** · 03-09-2016, 07:04 AM

I am trying to write NORMINV in PHP and have attempted to look-up exactly what the formula is for this function in Excel.

Can anyone shed some light / point me in the right direction?

**forestview** · 03-09-2016, 08:46 AM

Not being a statistician but from info I have it states as follows:

NORMINV() will return the inverse of the normal cumulative distribution

NORMINV(probability,mean,standard_dev)

**MrShorty** · 03-09-2016, 09:38 AM

Whenever I have questions about Excel's functions, I start here: https://support.office.com/en-us/art...1-63f26a86c0eb

The equation Excel uses for the NORMDIST() and NORMINV() functions is explained in the help file for the NORMDIST() function, and it looks like it is the same equation described in Wikipedia: https://en.wikipedia.org/wiki/Normal_distribution

Does that help?