Question 476428
We need to find {{{alpha = Q[3] }}}such that {{{P( Z <= alpha) = 0.75}}}
From a table of cumulative standard normal values, we get  {{{P( Z <= 0.675) = 0.75}}}

==> {{{alpha = 0.675}}} ==> {{{(H - 63.6)/2.5 = 0.675}}}

==> H - 63.6 = 1.6875 ==> H = 65.2875, the 3rd quartile.