5. The mean age (at inauguration) of all U.S. Presidents is approximately normal with a mean of 54.8 years. About 17% of Presidents (at inauguration) were 48.6 years old or younger; and about 17% of Presidents (at inauguration) were 61.0 years old or older. What is the approximate standard deviation of this distribution? (hint: think 68-95-99.7 rule)

(b) President Obama was 54.6 years old on inauguration day. Would you consider him young, typical, old? Justify your answer.

(c) Theodore Roosevelt was 42 years old when he was inaugurated. Would you consider him unusually young? Justify your answer.

(d) William McKinley was 70 years old when he was inaugurated. How would you classify his age compared to all the other Presidents? Justify your answer. About 99.7% of all Presidents (on inauguration day) have been between the ages of __________ and __________ . (hint: use 68-95-99.7 rule)