The LOGNORMDIST function returns the lognormal distribution. @x is the value for which you want the distribution, @mean is the mean of the distribution, and @stdev is the standard deviation of the distribution.
Performing this function on a string or empty cell simply does nothing. if stdev = 0 LOGNORMDIST returns #DIV/0! error. if x<0, mean<0 or stdev<0 LOGNORMDIST returns #NUM! error.