Spray drift is a constant concern for pesticide applicators and agricultural producers. The inverse relationship between droplet size and drift potential is well known.The paper “Effects of 2,4-D Formulation and Quinclorac on Spray Droplet Size and Deposition” (Weed Technology, 2005: 1030–1036) investigated the effects of herbicide formulation on spray atomization. A figure in the paper suggested the normal distribution with mean and standard deviation was a reasonable model for droplet size for water (the “control treatment”) sprayed through a 760 ml/min nozzle.

a. What is the probability that the size of a single droplet is less than ? At least ?

b. What is the probability that the size of a single droplet is between 1000 and ?

c. How would you characterize the smallest 2% of all droplets?

d. If the sizes of five independently selected droplets are measured, what is the probability that at least one exceeds ?