1. A computer implemented method of valuing and modeling an investment, said method comprising the steps of: providing at least one investment for consideration on a computer, wherein each said investment is comprised of at least one future cash flow; creating at least one magnitude probability distribution by said computer for each said future cash flow, by a user, each said probability distribution to represent said uncertainty of magnitude at least one particular time to provide at least one magnitude distribution; creating at least one timing probability distribution in said computer for each said future cash flow, by said user, each said probability distribution to represent said uncertainty of timing at least one particular magnitude to provide at least one timing distribution; combining said at least one magnitude distribution and said at least one timing distribution by said computer into at least one joint-probability distribution function; converting said at least one joint-probability distribution function by said computer to generate a two-dimensional net present value probability distribution; and displaying said two-dimensional net present value probability distribution and said at least one joint-probability distribution function on a display device of a computer.