An experimenter is designing an experiment to test tetanus toxoid in guinea pigs. The survival of the animal following the dose of the toxoid is a random phenomenon. Past experience has shown that the random variable that describes such a situation follows the log-normal distribution with μy = 0 and σy = 0.65. As a requirement of good design the experimenter must choose doses at which the probability of surviving is 0.20, 0.50, and 0.80. What three doses should he choose?