$(20$ marks$)$ Common sense has claimed that the older the investor is$,$ the more conservative his or her investment strategy should be$.$ For example, younger investors might hold more in stocks, while older investors might hold more in bonds. In order to verify the common sense, ABC financial publication in Ottawa recently conducted a survey yielding the following information

$\backslash$table$[[,\backslash$table$[[$Age of$],[$Investor$]],$Percentage of Investments in the Stock Market,Total$],[,,\backslash$table$[[E_6$