In Excel 2010, the LOGINV function has been replaced by the LOGNORM.INV function, which has been improved, in terms of accuracy.
The Excel LOGINV function calculates the inverse of the Cumulative Log-Normal Distribution Function of x, for a supplied probability.
The format of the function is :
Where the function arguments are:
|probability||-||The value at which you want to evaluate the inverse function|
|mean||-||The arithmetic mean of ln(x)|
|standard_dev||-||The standard deviation of ln(x)|
The chart on the right shows the the Inverse Log-Normal Cumulative Distribution Function of x. The mean of ln(x) = 2 and the standard deviation of ln(x) = 0.2.
If you want to calculate the value of x, for a probability of 0.3, this can be done using the Excel Loginv function, as follows:
This gives the result 6.653346076.
Further information and examples of the Excel Loginv function can be found on the Microsoft Office website.
If you get an error from your Excel Loginv function this is likely to be one of the following:
Occurs if either:
- the supplied probability argument is ≤ 0 or ≥ 1
- the supplied standard_dev argument is ≤ 0
|#VALUE!||-||Occurs if any of the the supplied arguments are non-numeric.|