Researchers fed mice a specific amount of toxaphene, a poisonous pesticide, and studied their nervous systems to find out why toxaphene causes tremors. the absolute refractory period, time required for nerves to recover after a stimulus, was measured and varies normally. the measurements, in milliseconds, for five mice were 1.8, 1.9, 2.0, 2.1, and 2.3.
find the mean refractory period and the standard error of the mean.