The world health organization reports that the distribution of ages at time of death in the united states has a mean of 79.8 years and a standard deviation of 15.5 years, based on death certificates. the distribution of ages at time of death is obviously left‑skewed (, few people die young and most die old). researchers plan to take a random sample of 100 american death certificates. (a) what are the mean and standard deviation of the sampling distribution of the mean age at death, x¯ , for samples of 100 american death certificates? (enter your answer rounded to two decimal places.)