Please show work and explain steps. Thank you.

1. The average weight of 6 people in an elevator is 173 pounds. A 7^th person gets on and now the average weight is 165 pounds. How much did the 7^th person weight?

2. Use the following data obtained from ages of the last six U. S. Presidents at the time of their inauguration to answer the following questions:

Ages of Last 6 Presidents at Inauguration
George Bush	64
Bill Clinton	46
George W. Bush	54
Barack Obama	47
Donald Trump	70
Joe Biden	78

a. Find the mean of the data set. (Round to one decimal place.)

b. Find the standard deviation of the data set. (Do not round until the final answer. Round final answer to 1 decimal place.) Write problem without using the standard deviation capabilities of a calculator. Explanation is only an explanation of the process in English sentences, not reasoning for this part.

c. What percentage of presidents' ages fall within one standard deviation of the mean? (Round to 1 decimal place.)