Question 1007243
<pre>
z<sub>0.5</sub> is the value of z that has 0.5 (one half) of the
curve to the right of it.

{{{drawing(400,200,-5,5,-.5,1.5, graph(400,200,-5,5,-.5,1.5, exp(-x^2/2)), 
 locate(.1,.5,0.5),
green(line(0,0,0,exp(-0^2/2))),locate(4.8,-.01,z),locate(4.8,.2,z)
  
)}}}


Obviously that's right in the middle where z is 0.  So z<sub>0.5</sub> = 0.

Edwin</pre>