A physiological psychology laboratory has been studying avoidance behavior in rabbits for several years and has published numerous papers on the topic. It is clear from this research that the mean response latency for a particular task is 5.8 seconds with a standard deviation of 2 seconds (based on many hundreds of rabbits). Now the investigators wish to induce lesions in certain areas in the rabbits’ amygdalae and then demonstrate poorer avoidance conditioning in these animals (i.e., show that the rabbits will repeat a punished response sooner). They expect latencies to decrease by about 1 second, and they plan to run a one-sample t test (of m0 5 5.8).

a. How many subjects do they need to have at least a 50 : 50 chance of success?

b. How many subjects do they need to have at least an 80 : 20 chance of success?