Iv'e read the Wikipedia entry about the log-normal distribution, as well as a few other sources online, and still do not understand what sort of natural processes are expected to produce a log-normal distribution.
I understand how this distribution arises in processes with many independent factors whose effect is multiplicative, but not which processes are expected to behave in this way.
Both the Wikipedia entry and this review supply several examples of log-normally distributed phenomena, but the only one (aside from the multiplicative Galton board) for which I understand why the effect is multiplicative, is the distribution of bacteria colony sizes - The colonies double in number at each successive division, and the log of the colony size, the number of divisions, should be normally distributed.
Question:
Could anyone explain why the many examples of log-normally distributed data are multiplicative in nature, and more generally, how one comes to suspect , a-priori, such multiplicative phenomena as opposed to additive?