2. The cumulative relative frequency graph below shows the distribution of lifespans for 39 U.S. presidents. P] Cumulative relative frequency (%) 100- 80 60 60 40 40 20- 0 50 50 60 70 80 Lifespan (years) g. 90 (a) What is the median lifespan for U.S. presidents? Mark directly on the graph to show how you arrived at your answer. (b) The mean lifespan is 71.45 years, and the standard deviation is 12.35 years. President Ronald Reagan lived to be 93 years old. Calculate and interpret his z-score. (c) The mean lifespan is 71.45 years, and the standard deviation is 12.35 years. Mr. Rodriguez would like to know how many days, on average, presidents tend to live beyond their 70th birthday. Find the mean and standard deviation of the transformed data. Note: There are 365 days in a year. Starnes/Tabor, Updated Version of The Practice of Statistics, 6/e 2020 BFW Publishers Inc.