Consider the manufacture of Grandmother's Fudge Nut Butter Cookies. Grandmother has noted that the number of nuts in a cookie is a random variable with a Poisson mass function and that the average number of nuts per cookie is 1.5.
The customers have been getting restless; so grandmother has instructed her inspectors to discard each cookie which contains exactly zero nuts. Determine the mean and variance of the number of nuts per cookie for the remaining cookies. Hint: We are looking for numbers here that may be calculated based on the original Poisson.