Hi! I am trying to write a UDF. The function works fine if I just write it as
a worksheet function. For several reasons I need it as a UDF though. Excel
tells me "Sub or function not defined" where Ln is. How am I supposed to
write this? It looks fine to me..Ay help appreciated!

Public Function Kupiec(p As Double, T As Double, N As Double) As Double
Dim a As Double
Dim b As Double

a = -2 * Ln((1 - p) ^ (T - N) * p ^ N)
b = 2 * Ln(1 - (N / T)) ^ (T - N) * (N / T) ^ N

Kupiec = a + b

End Function